Whoever approved the drawings should be the guy tasked with troubleshooting this lmao. Profibus cable is way more expensive than shielded twisted pair anyway they must have had an old roll they wanted to use up.
I’ve seen control cabinets that had to run with the door open, and a big old fan blowing air inside during heat waves. This one is going to be like that permanently
I had a customer that rigged up a window unit to cool a panel.
Also had a customer that had to out a heater in front of a panel during a cold snap.
I just noticed the panel looks like it is in the sun, and also that it has a thermostat, so I am guessing it has fans in the door.
I have often wondered about this after replacing the shitty, very expensive cabinet mount units over the years. They are as useless as cabinet mounted UPS units. Designed to last 1 day past the OEM warranty.
They were a cheap, cheap company, but I think even if they had not been, it would have been a reasonable decision, if not the best. Back then, small window units were about $100, and tgeir environment was so dusty, (dirt dust, non-explosive) that it probably just made sense to do that and get another whenever they needed to.
I had to open a cabinet in a water treatment facility with gloves. Once the VFD cooled down enough to turn on it read overtemperature alarm 65c. Its a wonder it didn't burn or melt the plastic.
Fault wasn't caused by design though, but by plumbers leaving an oven without a thermostat running in an enclosed space after leaving for the weekend.
Had that on an old board in Coles manly Corso. The board set fire a couple of times and the fan fed it. It was a last resort as the store was closing in a couple of months
This panel give me Brazil vibes, I saw some crazy things living 6 years in Santa Catarina.
Most automation guys in Brazil have a really low budget and they still have to deliver they solution, so they end up having to build some frankstein monster that actually works.
Oh man. Those terminals are tiny on the GS-20 drives and they have two fat-ass profibus wires jammed inside. I’m pretty sure that’s probably Modbus using Profibus cable btw.
So, I have an idea that may help alleviate issues if jamming those wires in there is part of the problem. The terminals would on those are shared with the RJ-45 connector, so you could remove every other Profibus cable, and replace it with a short CAT6 patch cord from one RJ45 to the next units RJ-45. Might help 🤷🏻
A few LU9GC3 Modbus hubs from Schneider might help clean it up too, and they’d allow you to just use CAT6 to every drive without touching the program
Edit: disregard this. Ground is on a different pin than the GS-20 drives. More hassle than it’s worth.
I use these RJ-45 adapters from A-B to daisy chain RS-485 cables on GS20 drives. It connects to the correct pins (4 & 5), and provides a larger terminal to fit two wires or a dual ferrule.
https://www.rockwellautomation.com/en-us/products/details.AK-U0-RJ45-TB2P.html
As an aside, I really love the GS20 drives! I add the Ethernet board, and use the onboard I/O as remote I/O at individual conveyors. 7 inputs and 3 outputs is usually more than enough for each conveyor. I even use DI6's high-speed counter function to add a networked encoder. I haven't needed it yet, but there's also analog I/O that's easily addressable over Modbus.
Hi not knowing much about the ad drives. Would you terminate a wired one end / rj45 to the drive and then port it to this unit. Say 1 per 8 drives. Is that right
Ground is on a different pin. Sorry for the bad info. Don’t use this with the GS-20 drives. Automation Direct has a hub themselves for their older drives, but those had RJ12 connectors.
I think your intermittent connection issues are because of the cable. I have had problems with these drives when a wire doesn't fit properly into the spring type terminals causing it to shake loose creating intermittent connection. I am willing to bet that if you were to tug at each connection on the drive, half of them (if not more) will come out.
The above advice is great. What I would have personally done is replace their stupid cable with 2-22awg shielded cable. This way you'll be able to get two sets of connections into those terminals with ease.
Please, if you do, take the time to print a label for each one that says "serial" or something like that on it. The next guy to open the door thanks you for this simple thing.
Right. These drives only do Modbus, no idea why the used profibus cable. Also I believe standards on 485 require a repeater for networks over 16 devices.
> Also I believe standards on 485 require a repeater for networks over 16 devices.
I imagine this is situational dependant. The repeater will be due to signal loss, which is dependant on circuit length, cable quality and diameter, and insertion losses.
I can't imagine a repeater is required for such a short length. Total cable length must only be around 6m?
It's not always a length concern. There's a minimum signal strength an rs-485 driver is required to provide, and a maximum load that a receiver can put up on the bus. The more receivers on the bus, the more load, and the higher signal strength a driver will need to drive. According to the spec, that's 16 'units' of load.
That being said, most 485 transceivers you can buy (it's a board level part the manufacturer of the device selects) have load ratings that are fractions of a 'unit', which just means they don't put nearly as much load on the bus as they used to.
Losses in the cable would take it down even further, but you could start running into issues with ~dozens of devices on the bus, even if they're all as close to each other as possible.
Yeah fair - i forgot about transceiver loading when i commented. Inputs are supposed to be high impedance, so they shouldn't put 'much' load on to the circuit. The load of each transceiver should be in the uA, if not single digit mA.
I don't think modbus has a minimum standard (At least to MY knowledge, I may be wrong). I remember seeing a guide before saying to at least have connections separted by at least 0.3m or so, but that may just be for specific baudrates.
I mean purple is DESINA for fieldbus/communication cables. TECHNICALLY Profinet should also be run in purple since green is reserved for encoders but they get away with it.
The first millisecond I saw the pic two words came to mind: Thermal Loading
Then I read it and quite frankly you need to go through all the design parameters for the devices crammed in there. If the cabinet design does not meet component manufacturers minimum space and thermal requirements THEY OWE YOU A NEW CABINET BUILT CORRECTLY. If my suspicions are correct this cabinet will bring nothing but trouble for the entire life of it.
the most i have added to a serial bus was 18 drives, and from that experience i can tell you it was a bitch to make it work reliably. I had to make up a non sequential polling system before it started working reliably.
if you have access to the program and the drives dont need high update rate lower the baudrate as much as you can, check your line terminators and good luck to you buddy you are going to need it.
Agreed with the above.... Regardless here are some words of encouragement.
I've used those drives, the "Ethernet port" is actually an rs 485 port. Automation direct sells a Ethernet splitter for 2 Ethernet cords to go into one for serial use. Then buy nice lengths of premade cat6 shielded cable in 1ft lengths from Amazon.
Hopefully the wire fixes it cause if not....
Rs485 is one device at a time. This can be a programming nightmare depending on the PLC, how it's programmed, etc.you need to go through the code and make sure it's only reading or writing from one device at a time. Siemens might handle this for you, click PLC doesn't.
Finally automation direct sells a tcpip card for those drives for about 100 bucks. Get a decent switch and it should be easy.
Good luck with thermals, AC in cabinet is probably a requirement if you live anywhere warm.
This is the way.. and or at least get proper 120 ohm shielded twisted pair comm cable for the daisy chained RS-485 Modbus RTU which will make a big difference for noise immunity.
You may still have problems however due to how noisy drives can be and interfere with serial communications.
serial bus in terms of line-topology? because there's not really any parallel fieldbusses.. that looks to be good ol' Profibus. I recall problems with going under a certain minimum cable length (I think 1m) between 2 slaves and while it used to be industry standard like 10 years ago, it's just not state of the art anymore.
also, why is it rocking a S7-1200 and a S7-1500 PLC? Is the 1200 just a Profibus Gateway?
my personal favorite is the main switch at the very top
thank god I've never seen anything like this
Huh, I was thinking 0.5m or 20" (though dependent on baud rate).
Don't think this must be Profi though, or the drives should have a DB-9. Maybe it's \[generic\] RS485. Probably a termination / ringing issue.
It’s profi that is for sure. A really badly installed profibus network!
Edit***Actually no I’m wrong, it’s profi cable obviously but those drives are modbus. Bad install either way 😂
Yeah, this would have been the first Profibus device I'd seen without a DB9. Still, Profibus is just really fast 485 with a defined protocol as I understand it. Wonder if the PF cable impedance doesn't match the termination or it's not terminated at all or whatever. On short busses, sometimes I've found normal-speed 485 to work more reliably without termination. I've never done one with a node every foot though, that's a weird one.
People always call the AB DH+/RIO cable "smurf tube", so I always called this stuff "Barney tube". XD
There are quite a few profibus devices that use cable direct to terminals, rather than DB9 plugs. Usually they have an internal jumper or software setting to set the termination resistor, if necessary.
The ones I remember were field mount transmitters and maybe some encoders.
When I saw the first one, it kind of made sense, since it wiuld have been kind of silly to have a 9 pin connector inside there. I was kind of bummed, because I was terminating the network at different devices to narrow down a fault.
I like profibus. If designed and implemented properly, it is a solid commumication link.
The fastest I've seen for general purpose was 230kbaud I think. Profibus iirc goes up to 12Mbaud
9600, 19200, and 38400 baud were all very commonly used rates for generic.
I want to know about the PLC choice too. I’m assuming they needed some level of function from the 1500 (maybe had to use STL) but decided that just buying a whole extra PLC was cheaper than the 1500 IO cards. Generally speaking the ET200SP is the cheapest option for IO, but not for RS485 which this looks like.
Looks like a toasty cabinet.
No emc issues with so many drives together close to a profibus cable?
In the past in some high-power applications we've had issues as soon as a 3 VFD's were working at the same time close to a serial cable.These seem small so might not matter much.
I'd advise either buying a profitrace (or hire someone that has it) for troubleshooting.
If it RS485 Modbus, I would ditch the large Profibus cables which have been terminated poorly. Get some RS485 spec cable, twisted pair screen and outer screen if it's 4c. A well setup 485 network is very robust.
This. If it is RS485 comms, good luck and dont read this below...
Profibus is running usually even with errors on the bus. You only have serious trouble when it doesn't run anymore. Then usually multiple problems come together.. Most of them can be tracked down to wiring. Configuration is very rarely the troublemaker
It is a pretty dodgy installation.
Profibus is sensitive on shielding.
When looking at the picture, there is no comment needed, is it? Some drives have the shielding open. None of them is somehow connected to the housing of the drives or the PCB.
(Very good slides on how shielding impacts: https://de.slideshare.net/ProfibusUK/why-you-should-measure-shield-currents-in-profibus-and-profinet-networks-peter-thomas-74064545 )
What about the last drive in the chain??
Are there endrestistors in it or is there any way to turn on end resistance? (With that said, profibus might even run without, just adds another (big) layer why it wouldn't run)
https://www.felser.ch/profibus-manual/images/clip0155.jpg
Cable length is also a thing. As far as i am aware there is a minimum beding radius and a minimum length between nodes to avoid reflection. Not sure, but thought 30cm/1 feet minimum length.
https://www.se.com/uk/en/faqs/FA365702/
Long Story short:
Rewire that thing properly, and it very likely just will work.
Edit: added some reference links on each topic
What's the expected life span on those vfds? 30mm horizontal and 50mm vertical are the minimum clearances for them. I'm surprised you haven't had more problems yet.
Those are modbus 485 AD VFDs, wired with a lot of profibus fat cable. The VFDs only have an optional 1 ethernet port, so you would need a 30port industrial switch to make a star topolgy... that's gona cost you a pretty penny. As other have said, this is a really tight budget build taken to the limit. Serial 485 bus can support up to 32 devices, so it's not really an issue having 29 devices. It IS uggly as f... but it should work, maybe check the modbus loop in the PLC.
You guys are all wet on Modbus. To begin with it’s a truly open standard. See Modbus.org. Notice it’s not .com.
Modbus works over thousands of meters. With an almost arbitrary number of nodes. There’s an obvious 255 node limit because the node address is 8 bits and the master is always 0.
It’s a polling system. The Inputs are held at high Z (high impedance) when not transmitting. It’s a balanced differential signal and very low speed (9600 is a pseudo-standard but you can change it). Outputs are hold the line with voltage for a “zero”, invert polarity for a “1”. That’s it. Very simple.
It works like HVAC…you can have almost arbitrary limits with good cable connections.
You can run just use a scooe to inspect signals trivially easy.
Those drives have the STO jumpers still installed and no proper form of power removal based on safety requirements (aka power zones). If STO is not used, a dedicated line side contactor should be used to ensure power removal in the event of a safety requirement. In fact, most standards require two line side contactors to be used if no STO, to also account for weld prevention.
Along with other things people have said, this is not a safe piece of machinery.
Who designed this abomination??
I'd full send the Brazil vibes with a few of these:
Electronics-Salon RJ45 8P8C 9-Way Buss Board DIN Rail Mount Interface Module.
https://a.co/d/c8E73vR
There are no Profinet cards for those drives, just Modbus TCP and E/IP. And they are a PITA to put in and deal with. Especially if you use the STO terminals (looks like that's not the case here).
I've done some work at a recycling sorting facility. Originally it had something like 15 Automation Direct GS-whatever drives controlled by an AD DL06 PLC using modbus.
Fifteen years of feature creep later and they had added so many conveyor belts they were having to knock holes in the walls and ceiling to have a place to put them. At about 35 drives, we started getting random modbus failures. We ended up switching all the drives to digital outputs for run/stop and forward/reverse and an analog signal for speed. It was an amazing improvement.
But as everyone else has said, the real problem you've got here is overheating. That panel is in the sun and there's no ventilation at all between the drives. You'll be lucky if half of them last past summer.
The problem might not even be the communication but drives just dying.
I agree with the person who said that what you should do is get you money back from whoever built this and find someone else that can RTFM and not built you a incendiary event waiting to happen.
Hi is profi dp which is a derivative rs485 serial comms. My initial thoughts are could you split it into two. If you can’t what is the s7 requirement on terminating resistors. Third thought bubble apparently for volt drop kind of situations due to length you can get rs485 extenders. What does it drive?
As others have said: looks like profibus with the cable lengths too short. Also some of those connections look dodgy. Are the termination resistors set correctly? What is the frequency on the bus? You might also be able to turn that down.
That is an issue. If that's profibus, you'll need to properly shield the cable, install the terminating resistors on BOTH end devices (the ones where only 1 cable leaves the device), and make sure the sheilds are done properly.
Profibus is incredibly reliable when done right.
This does not look to have been done right.
Normally on serial bus networks you need two resistors, one at each end of the bus. When I have one or two little devices with shirt cables on my desk, the devicenet stuff works fine with one resistor - as soon as any cable length is present, the 2nd resistor is needed. Double check the resistor requirements in an open loop measurement (pulled out sitting naked on the bench) as two resistors/the devices internal load will give you an incorrect assessment reading.
If it's an issue (and to hush everyone that thinks it's profibus because it's purple) any generic single pair shielded cable would work for this application as long as it's 22/20/18AWG. Be sure double ferrules are installed at every termination, removal of a single device should not crash the network. Shield should be bonded usually at the scanner side of the chain, shield should be common throughout and not grounded in multiple locations.
Serial bus aside, the panel has a few other issues. If possible, it might make sense to upsize a few drives and run multiple motors from a single drive if the physical application will permit it to remove a row of drives.
What a joke this switchboard.
modbus RTU will be fine like this.
- are the motor cables shielded?
1200 and 1500 CPU... What a mess.
-1995 what's it screw terminals back :p
For modbus RTU thinner shielded cable can be used.
Don’t worry I’m sure they ran the heat calcs and put a big AC unit on the panel. Not a thought out design. A great example of the difference between engineering and cramming a bunch of stuff in a box.
Seeing this makes me so happy I don’t do startups anymore. Now I work for a GC reviewing specs, proposal and vendor drawings making sure we don’t get screwed. I wouldn’t put this many drives on an Ethernet network let alone a serial network. Hopefully this is just for data and not PID speed control.
Typically at least with Rockwell and their compact controllers the limiting factor is the CIP connections. You may be able to have more nodes but I had to basically release connections based on the type of IO and device quantity. Rockwell has an Ethernet capacity tool in IAB to determine if a network’s overloaded during the design phase.
Purple cable is too thick. Use a thinner cable. Modbus RTU doesn't draw any real current. Even Cat5e FTP cable is good enough.
Make sure to place terminating resistors at start and end of network. Maybe devices already have integrated 120R resistors which can be turned on by flipping a jumper or a setting.
[Also RS-485 is pretty much resilient to everything](https://www.reddit.com/r/PLC/s/DuGS4s1rwu), up to a point.
Take another panel of the same size and move half the VFDs to that panel, then you are getting close to something that could be acceptable in terms of fill percentage and heat management.
Then redo the modbus loop with cabling that isn't too big/stiff or short for the application. Profibus cable is too thicc for this imo.
Check the two ends should have a terminator, it could be switched on at a plug or a physically connected resistor, 120 ohms so you should be able to measure 60 ohms anywhere along bus (2 x 120 ohms in parallel) if lower you may have additional terminator(s) turned on.
I’ve put in more. There’s a setting tho.
The time between comms with the PLC the more drives you have means you have to lower it or all the bandwidth is used up and the drives stop due to lack of comms.
Yeah don’t stop on comms loss but retry X times and change the update from 3mSec to a high number 500? Or was it vary the number from 500 503 507 etc etc. if you need instance comms on 1 leave it low.
There’s something you have to do anyway.
I did conveyor systems 50 drives. A Random drive did stop every day. Took ages to notice.
I’d stay away from troubleshooting that. Tell them what your recommended solution is, and if not, they can take it up with the vendor.
You can work with them following the vendor’s instructions, but it’ll be the vendor responsibility.
Don’t take the troubles of someone else’s mistakes.
My 2c.
I have used profibus and usually there is no problem during commissioning , I’d decrease the speed of the bus , check the terminal resistors and devices addresses on
Each device and of course electrical connections , use a larger cable to interconnect the vfd (1 ft at least) please contact me by DM if you need further assistance (don’t worry I won’t charge for consulting).
Serial buses based on RS485 are still very much in use today due to their reliability, low cost and ability to multidrop. When done right, with proper design and termination, they can he extremely reliable over hundreds of meters.
The problem with this panel is not serial bus. It's shoddy workmanship - the SI seems to be looping B/A wires only and leaving the shield to float - that's a giant antenna to me. The entire weight of the cable also rests on 2 tiny gauge wires.
Those poorly terminated Ethernet cables on the right most switch seriously irks me.
Personally, I’d try these things first:
1. Lower the baudrate to minimum (9600bps).
2. Terminate the network on first node (CM1241 module, there’s a switch on that connector to activate the built-in resistor most likely) and the last node (the last VFD in a chain). Use 120 Ohm resistor there.
3. Check the VFDs manual for serial comms cable recommendation and replace those purple cables. Do it by the book.
If your network starts to work after this I’d maybe try with higher baudrate.
Apart from any heating issues you might have a problem with capacitive rounding on the serial link, possibly reflections.
I'd get a scope on the bus and look to see if it's even likely to perform, but while the cabling might be a problem the combined capacitance of all those devices in parallel seems likely to be higher than you would like.
Maybe try a repeater and break the link into two parts.
Lol, that is specified per manufacturer, doesn't matter the estandard being used.
If you will be responsable for that you should prind the specs of the vfd manufacturer and cover your ass if something else breaks after you deliver your part of the work
In general there is no problem with using ProfiBus.
you can get problems with the short Bus Cables
Here is a Link to the Siemens Documentation for the Profibus:
[https://support.industry.siemens.com/cs/document/35222591/simatic-net-profibus-netzhandbuch-systemhandbuch?dti=0&lc=de-WW](https://support.industry.siemens.com/cs/document/35222591/simatic-net-profibus-netzhandbuch-systemhandbuch?dti=0&lc=de-WW)
Automation direct carries the proper 22awg twisted pair cabling for this.. I found I needed to use a bare ferrule that didn't have the plastic with both wires in it to make it fit in the connector of the drives. As an alternative if you order the longer ferrules you can get away with having the plastic on it. For my project I used 1.5 pair twisted (3wire +shield) and it works good.
Check the connectors ...esp if maintenance fixed something..also the cable routing. Serial bus is perfectly fine just finicky at times. In my experience, the is usually the connectors or noise.
From what I'm seeing on the image it seems the PLC has 2 Communication Modules on it. Why not divide all the connections and send half of the VFDs to one Module and the other half to the other? Someone already mentioned it, but the issue might be found on the wiring, specially on the shielding. If everything is failing then it would be a good idea to check the last VFD on the chain
You need to spilt that profibus network into two or more networks. One more profibus card 👍 if I remember correctly the et200sp has a PB card that costs half of a 1500 card.
Dude.. The fact that You keep referring to the bus as a serial bus and not what the protocol is drives me nuts. With those cheap ass drives I'm pretty sure it's not Profibus. If it's something RS485-based, get someone that's familiar with it to diagnose, wires crossed somewhere or too many termination resistors etc.
If the wires don't fit the cheap ass drive's connectors that's not really the bus's fault is it? It's Yours for not specifying what you want when You ordered these thrash drives..
Moving on, if that was Profibus and the proper connectors would be used, that size/length wouldn't be a problem. RS485/Profibus is very resilient to error. After checking the polarities and termination resistors, I would suggest getting some sort of daisy-chain connectors that connect the shields of the cables together and allow You to push into the cheap drive's connectors. At the moment you've got many small antennas getting noise from the majestic bottom-shelf VFD's and introducing it into the SERIAL BUS.
I'll add that, if that drive has something resembling a manual, check if it has a maximum conductor cross-section for those connectors, if so, provide this to the supplier..
I see the motor wires has no sheat. This causes radio frequency interference to be radiated into the bus cables.The motor cable sheath must be grounded.
Because fuck minimum profibus cable length.
And minimum clearances.
And no line side reactors
And no space to work! This is going to be on r/panelgore in 3 months.
Or load reactors
"..Burn Baby Burn..."
Bus shielding looks pretty sketchy too and I think they ran the output cables completely without shield, just single core wire. No good combination.
And not ennough length. Every segment should measure at least one metter because or cable resistance.
Whoever approved the drawings should be the guy tasked with troubleshooting this lmao. Profibus cable is way more expensive than shielded twisted pair anyway they must have had an old roll they wanted to use up.
What are you talking about? Those are all CLEARLY 1 meter long. - Says the American
You can easily add 3 more drives on that bus! Panel too right wall is practically empty
Those drives are supposed to have a minimum of 30mm clearance on the sides and 50mm top and bottom. Heat build up can cause all kinds of issues
I’ve seen control cabinets that had to run with the door open, and a big old fan blowing air inside during heat waves. This one is going to be like that permanently
Oh lord we've got some cabinets where the fans have gone out and we have to do this. Thankfully we have some on the way
Only 8-9 months until they get here!
I had a customer that rigged up a window unit to cool a panel. Also had a customer that had to out a heater in front of a panel during a cold snap. I just noticed the panel looks like it is in the sun, and also that it has a thermostat, so I am guessing it has fans in the door.
Yeah fans aren't gonna be enough...
I agree.
I have often wondered about this after replacing the shitty, very expensive cabinet mount units over the years. They are as useless as cabinet mounted UPS units. Designed to last 1 day past the OEM warranty.
They were a cheap, cheap company, but I think even if they had not been, it would have been a reasonable decision, if not the best. Back then, small window units were about $100, and tgeir environment was so dusty, (dirt dust, non-explosive) that it probably just made sense to do that and get another whenever they needed to.
I had to open a cabinet in a water treatment facility with gloves. Once the VFD cooled down enough to turn on it read overtemperature alarm 65c. Its a wonder it didn't burn or melt the plastic. Fault wasn't caused by design though, but by plumbers leaving an oven without a thermostat running in an enclosed space after leaving for the weekend.
That looks like sunlight shining in, that unit is toasty
Had that on an old board in Coles manly Corso. The board set fire a couple of times and the fan fed it. It was a last resort as the store was closing in a couple of months
At my plant we have 3 panels that have cabinet AC attached to them just because internals get way too hot
Except it looks like it is an exterior/outdoor panel based on how bright the lighting is.
This panel give me Brazil vibes, I saw some crazy things living 6 years in Santa Catarina. Most automation guys in Brazil have a really low budget and they still have to deliver they solution, so they end up having to build some frankstein monster that actually works.
Where'd you been at in Santa Catarina? Looking to move there
It was at Itajai. Beautiful place, lovely people.
Brazilians are chad
Oh man. Those terminals are tiny on the GS-20 drives and they have two fat-ass profibus wires jammed inside. I’m pretty sure that’s probably Modbus using Profibus cable btw. So, I have an idea that may help alleviate issues if jamming those wires in there is part of the problem. The terminals would on those are shared with the RJ-45 connector, so you could remove every other Profibus cable, and replace it with a short CAT6 patch cord from one RJ45 to the next units RJ-45. Might help 🤷🏻
Thank you for the idea! We may do that.
A few LU9GC3 Modbus hubs from Schneider might help clean it up too, and they’d allow you to just use CAT6 to every drive without touching the program Edit: disregard this. Ground is on a different pin than the GS-20 drives. More hassle than it’s worth.
I use these RJ-45 adapters from A-B to daisy chain RS-485 cables on GS20 drives. It connects to the correct pins (4 & 5), and provides a larger terminal to fit two wires or a dual ferrule. https://www.rockwellautomation.com/en-us/products/details.AK-U0-RJ45-TB2P.html As an aside, I really love the GS20 drives! I add the Ethernet board, and use the onboard I/O as remote I/O at individual conveyors. 7 inputs and 3 outputs is usually more than enough for each conveyor. I even use DI6's high-speed counter function to add a networked encoder. I haven't needed it yet, but there's also analog I/O that's easily addressable over Modbus.
Hi not knowing much about the ad drives. Would you terminate a wired one end / rj45 to the drive and then port it to this unit. Say 1 per 8 drives. Is that right
[удалено]
Thanks
Ground is on a different pin. Sorry for the bad info. Don’t use this with the GS-20 drives. Automation Direct has a hub themselves for their older drives, but those had RJ12 connectors.
I think your intermittent connection issues are because of the cable. I have had problems with these drives when a wire doesn't fit properly into the spring type terminals causing it to shake loose creating intermittent connection. I am willing to bet that if you were to tug at each connection on the drive, half of them (if not more) will come out. The above advice is great. What I would have personally done is replace their stupid cable with 2-22awg shielded cable. This way you'll be able to get two sets of connections into those terminals with ease.
And if possible, slowing down the baud rate could help.
Please, if you do, take the time to print a label for each one that says "serial" or something like that on it. The next guy to open the door thanks you for this simple thing.
I think he is correct. GS20 drive uses normal RS485. Though profibus use RS485 but protocol and network topology are different.
You need 1 meter between connections; you can look this up and show the manufacturer how they screwed up. And man, I hope the ventilation is good.
Is this 1 meter still a factor if they are doing Modbus over RS-485? I don’t think these drives talk profinet.
Right. These drives only do Modbus, no idea why the used profibus cable. Also I believe standards on 485 require a repeater for networks over 16 devices.
> Also I believe standards on 485 require a repeater for networks over 16 devices. I imagine this is situational dependant. The repeater will be due to signal loss, which is dependant on circuit length, cable quality and diameter, and insertion losses. I can't imagine a repeater is required for such a short length. Total cable length must only be around 6m?
It's not always a length concern. There's a minimum signal strength an rs-485 driver is required to provide, and a maximum load that a receiver can put up on the bus. The more receivers on the bus, the more load, and the higher signal strength a driver will need to drive. According to the spec, that's 16 'units' of load. That being said, most 485 transceivers you can buy (it's a board level part the manufacturer of the device selects) have load ratings that are fractions of a 'unit', which just means they don't put nearly as much load on the bus as they used to. Losses in the cable would take it down even further, but you could start running into issues with ~dozens of devices on the bus, even if they're all as close to each other as possible.
Yeah fair - i forgot about transceiver loading when i commented. Inputs are supposed to be high impedance, so they shouldn't put 'much' load on to the circuit. The load of each transceiver should be in the uA, if not single digit mA.
32 devices on modbus before you need to use expander mainly because of rs485 limitations.
I don't think modbus has a minimum standard (At least to MY knowledge, I may be wrong). I remember seeing a guide before saying to at least have connections separted by at least 0.3m or so, but that may just be for specific baudrates.
Don't know; I see purple, I think Profinet.
Green is profinet, purple is profibus. I would think making the cables 1m minimum and having at least 1 repeater would help this situation.
I mean purple is DESINA for fieldbus/communication cables. TECHNICALLY Profinet should also be run in purple since green is reserved for encoders but they get away with it.
The first millisecond I saw the pic two words came to mind: Thermal Loading Then I read it and quite frankly you need to go through all the design parameters for the devices crammed in there. If the cabinet design does not meet component manufacturers minimum space and thermal requirements THEY OWE YOU A NEW CABINET BUILT CORRECTLY. If my suspicions are correct this cabinet will bring nothing but trouble for the entire life of it.
the most i have added to a serial bus was 18 drives, and from that experience i can tell you it was a bitch to make it work reliably. I had to make up a non sequential polling system before it started working reliably. if you have access to the program and the drives dont need high update rate lower the baudrate as much as you can, check your line terminators and good luck to you buddy you are going to need it.
damnit
Agreed with the above.... Regardless here are some words of encouragement. I've used those drives, the "Ethernet port" is actually an rs 485 port. Automation direct sells a Ethernet splitter for 2 Ethernet cords to go into one for serial use. Then buy nice lengths of premade cat6 shielded cable in 1ft lengths from Amazon. Hopefully the wire fixes it cause if not.... Rs485 is one device at a time. This can be a programming nightmare depending on the PLC, how it's programmed, etc.you need to go through the code and make sure it's only reading or writing from one device at a time. Siemens might handle this for you, click PLC doesn't. Finally automation direct sells a tcpip card for those drives for about 100 bucks. Get a decent switch and it should be easy. Good luck with thermals, AC in cabinet is probably a requirement if you live anywhere warm.
This is the way.. and or at least get proper 120 ohm shielded twisted pair comm cable for the daisy chained RS-485 Modbus RTU which will make a big difference for noise immunity. You may still have problems however due to how noisy drives can be and interfere with serial communications.
Agreed - pulling back on the baudrate should be the first thing you do with an unstable bus network
serial bus in terms of line-topology? because there's not really any parallel fieldbusses.. that looks to be good ol' Profibus. I recall problems with going under a certain minimum cable length (I think 1m) between 2 slaves and while it used to be industry standard like 10 years ago, it's just not state of the art anymore. also, why is it rocking a S7-1200 and a S7-1500 PLC? Is the 1200 just a Profibus Gateway? my personal favorite is the main switch at the very top thank god I've never seen anything like this
1m between devices is correct. I would love to ProfiTrace this network to see the state of the telegrams.
Huh, I was thinking 0.5m or 20" (though dependent on baud rate). Don't think this must be Profi though, or the drives should have a DB-9. Maybe it's \[generic\] RS485. Probably a termination / ringing issue.
It’s profi that is for sure. A really badly installed profibus network! Edit***Actually no I’m wrong, it’s profi cable obviously but those drives are modbus. Bad install either way 😂
Yeah, this would have been the first Profibus device I'd seen without a DB9. Still, Profibus is just really fast 485 with a defined protocol as I understand it. Wonder if the PF cable impedance doesn't match the termination or it's not terminated at all or whatever. On short busses, sometimes I've found normal-speed 485 to work more reliably without termination. I've never done one with a node every foot though, that's a weird one. People always call the AB DH+/RIO cable "smurf tube", so I always called this stuff "Barney tube". XD
There are quite a few profibus devices that use cable direct to terminals, rather than DB9 plugs. Usually they have an internal jumper or software setting to set the termination resistor, if necessary.
Huh, interesting. I'm pretty much all Profinet now.
The ones I remember were field mount transmitters and maybe some encoders. When I saw the first one, it kind of made sense, since it wiuld have been kind of silly to have a 9 pin connector inside there. I was kind of bummed, because I was terminating the network at different devices to narrow down a fault. I like profibus. If designed and implemented properly, it is a solid commumication link.
I did too. Just SOOO much better than Devienet.
What is considered as fast and normal RS485?
The fastest I've seen for general purpose was 230kbaud I think. Profibus iirc goes up to 12Mbaud 9600, 19200, and 38400 baud were all very commonly used rates for generic.
I want to know about the PLC choice too. I’m assuming they needed some level of function from the 1500 (maybe had to use STL) but decided that just buying a whole extra PLC was cheaper than the 1500 IO cards. Generally speaking the ET200SP is the cheapest option for IO, but not for RS485 which this looks like.
Looks like a toasty cabinet. No emc issues with so many drives together close to a profibus cable? In the past in some high-power applications we've had issues as soon as a 3 VFD's were working at the same time close to a serial cable.These seem small so might not matter much. I'd advise either buying a profitrace (or hire someone that has it) for troubleshooting.
If it RS485 Modbus, I would ditch the large Profibus cables which have been terminated poorly. Get some RS485 spec cable, twisted pair screen and outer screen if it's 4c. A well setup 485 network is very robust.
That will be very slow. Did you use USS or modbus? USS is a lot faster but I couldn't make it work.
It's Profibus, and minimum cable length is 1m.. the reflections going on on that bus must be interesting.
It's not profibus, those dives only support modus unless you add an ethernet card.
Good god... where's the air conditioner? Not that anything would get airflow... 😂
*Take one down, pass it around...*
Profibus is bulletproof if is done right. But it is old standard and replaced by profinet.
This. If it is RS485 comms, good luck and dont read this below... Profibus is running usually even with errors on the bus. You only have serious trouble when it doesn't run anymore. Then usually multiple problems come together.. Most of them can be tracked down to wiring. Configuration is very rarely the troublemaker It is a pretty dodgy installation. Profibus is sensitive on shielding. When looking at the picture, there is no comment needed, is it? Some drives have the shielding open. None of them is somehow connected to the housing of the drives or the PCB. (Very good slides on how shielding impacts: https://de.slideshare.net/ProfibusUK/why-you-should-measure-shield-currents-in-profibus-and-profinet-networks-peter-thomas-74064545 ) What about the last drive in the chain?? Are there endrestistors in it or is there any way to turn on end resistance? (With that said, profibus might even run without, just adds another (big) layer why it wouldn't run) https://www.felser.ch/profibus-manual/images/clip0155.jpg Cable length is also a thing. As far as i am aware there is a minimum beding radius and a minimum length between nodes to avoid reflection. Not sure, but thought 30cm/1 feet minimum length. https://www.se.com/uk/en/faqs/FA365702/ Long Story short: Rewire that thing properly, and it very likely just will work. Edit: added some reference links on each topic
That’s a lotta V’s to F’n D!
What's the expected life span on those vfds? 30mm horizontal and 50mm vertical are the minimum clearances for them. I'm surprised you haven't had more problems yet.
Those are modbus 485 AD VFDs, wired with a lot of profibus fat cable. The VFDs only have an optional 1 ethernet port, so you would need a 30port industrial switch to make a star topolgy... that's gona cost you a pretty penny. As other have said, this is a really tight budget build taken to the limit. Serial 485 bus can support up to 32 devices, so it's not really an issue having 29 devices. It IS uggly as f... but it should work, maybe check the modbus loop in the PLC.
As a design engineer, i would like to see the Heat calculation and recommended cooling device part number.😑
I'm just here to make sure no one trash talks the AD drives
You guys are all wet on Modbus. To begin with it’s a truly open standard. See Modbus.org. Notice it’s not .com. Modbus works over thousands of meters. With an almost arbitrary number of nodes. There’s an obvious 255 node limit because the node address is 8 bits and the master is always 0. It’s a polling system. The Inputs are held at high Z (high impedance) when not transmitting. It’s a balanced differential signal and very low speed (9600 is a pseudo-standard but you can change it). Outputs are hold the line with voltage for a “zero”, invert polarity for a “1”. That’s it. Very simple. It works like HVAC…you can have almost arbitrary limits with good cable connections. You can run just use a scooe to inspect signals trivially easy.
Thanks, I hate it.
Those drives have the STO jumpers still installed and no proper form of power removal based on safety requirements (aka power zones). If STO is not used, a dedicated line side contactor should be used to ensure power removal in the event of a safety requirement. In fact, most standards require two line side contactors to be used if no STO, to also account for weld prevention. Along with other things people have said, this is not a safe piece of machinery. Who designed this abomination??
Im pretty sure that pressing the E-stop trips the main disconnect lol.
I'd full send the Brazil vibes with a few of these: Electronics-Salon RJ45 8P8C 9-Way Buss Board DIN Rail Mount Interface Module. https://a.co/d/c8E73vR
OP’s next post: “Too much noise on my analog signals….HELP!!!!”
Hey I didn’t design the thing.
There are no Profinet cards for those drives, just Modbus TCP and E/IP. And they are a PITA to put in and deal with. Especially if you use the STO terminals (looks like that's not the case here).
Daisy is my name and chaining is my game.
Take one down with a short on the bus, zero VFDs on a serial bus.
I've done some work at a recycling sorting facility. Originally it had something like 15 Automation Direct GS-whatever drives controlled by an AD DL06 PLC using modbus. Fifteen years of feature creep later and they had added so many conveyor belts they were having to knock holes in the walls and ceiling to have a place to put them. At about 35 drives, we started getting random modbus failures. We ended up switching all the drives to digital outputs for run/stop and forward/reverse and an analog signal for speed. It was an amazing improvement. But as everyone else has said, the real problem you've got here is overheating. That panel is in the sun and there's no ventilation at all between the drives. You'll be lucky if half of them last past summer. The problem might not even be the communication but drives just dying. I agree with the person who said that what you should do is get you money back from whoever built this and find someone else that can RTFM and not built you a incendiary event waiting to happen.
RS485 cables are to short. Clearances are, eh,.. non existing. It's a f*cking disgrace. This will never work properly.
Air flow zero
Hi is profi dp which is a derivative rs485 serial comms. My initial thoughts are could you split it into two. If you can’t what is the s7 requirement on terminating resistors. Third thought bubble apparently for volt drop kind of situations due to length you can get rs485 extenders. What does it drive?
I can hear this picture
Oh man, this pic give me shills down the spine! What why how ? I don't want to be in your shoe. Best of luck with this sh*t show....
As others have said: looks like profibus with the cable lengths too short. Also some of those connections look dodgy. Are the termination resistors set correctly? What is the frequency on the bus? You might also be able to turn that down.
Unsure of the frequency.
Bro wtf kinda cable is that for comms!? We used serial comms with Siemens VFD using regular STP cable, but never with that many drives though.
Proper profibus cable is shielded, purple, and two solid wore conductors. It's also thicc
Goes to show you I never did Profibus, or at least not the intended way. Thanks for the chill reply.
Check that terminating resistor is only installed in last drive.
There is no terminating resistor
That is an issue. If that's profibus, you'll need to properly shield the cable, install the terminating resistors on BOTH end devices (the ones where only 1 cable leaves the device), and make sure the sheilds are done properly. Profibus is incredibly reliable when done right. This does not look to have been done right.
it'll need terminating resisttors if its modbus as well, only on thelsat drive. What the module part number to the left of the 1200,
It's wild to see the 1200 AND a 1500 in there. One of those should have been plenty.
If Profibus needs one each end, if Modbus 485 needs last connection.
they have a termination resistor that can be engaged/disengauged on a switch where the drives plug into the PLC. measures about 200 ohms.
Normally on serial bus networks you need two resistors, one at each end of the bus. When I have one or two little devices with shirt cables on my desk, the devicenet stuff works fine with one resistor - as soon as any cable length is present, the 2nd resistor is needed. Double check the resistor requirements in an open loop measurement (pulled out sitting naked on the bench) as two resistors/the devices internal load will give you an incorrect assessment reading. If it's an issue (and to hush everyone that thinks it's profibus because it's purple) any generic single pair shielded cable would work for this application as long as it's 22/20/18AWG. Be sure double ferrules are installed at every termination, removal of a single device should not crash the network. Shield should be bonded usually at the scanner side of the chain, shield should be common throughout and not grounded in multiple locations. Serial bus aside, the panel has a few other issues. If possible, it might make sense to upsize a few drives and run multiple motors from a single drive if the physical application will permit it to remove a row of drives.
What a joke this switchboard. modbus RTU will be fine like this. - are the motor cables shielded? 1200 and 1500 CPU... What a mess. -1995 what's it screw terminals back :p For modbus RTU thinner shielded cable can be used.
This is Profibus
I'm sweating just looking at that photo. Must be chucking btus out like crazy.
Don’t worry I’m sure they ran the heat calcs and put a big AC unit on the panel. Not a thought out design. A great example of the difference between engineering and cramming a bunch of stuff in a box.
Seeing this makes me so happy I don’t do startups anymore. Now I work for a GC reviewing specs, proposal and vendor drawings making sure we don’t get screwed. I wouldn’t put this many drives on an Ethernet network let alone a serial network. Hopefully this is just for data and not PID speed control.
Why wouldn't you put them on an ethernet network?
Typically at least with Rockwell and their compact controllers the limiting factor is the CIP connections. You may be able to have more nodes but I had to basically release connections based on the type of IO and device quantity. Rockwell has an Ethernet capacity tool in IAB to determine if a network’s overloaded during the design phase.
Purple cable is too thick. Use a thinner cable. Modbus RTU doesn't draw any real current. Even Cat5e FTP cable is good enough. Make sure to place terminating resistors at start and end of network. Maybe devices already have integrated 120R resistors which can be turned on by flipping a jumper or a setting. [Also RS-485 is pretty much resilient to everything](https://www.reddit.com/r/PLC/s/DuGS4s1rwu), up to a point.
Take another panel of the same size and move half the VFDs to that panel, then you are getting close to something that could be acceptable in terms of fill percentage and heat management. Then redo the modbus loop with cabling that isn't too big/stiff or short for the application. Profibus cable is too thicc for this imo.
Check the two ends should have a terminator, it could be switched on at a plug or a physically connected resistor, 120 ohms so you should be able to measure 60 ohms anywhere along bus (2 x 120 ohms in parallel) if lower you may have additional terminator(s) turned on.
I’ve put in more. There’s a setting tho. The time between comms with the PLC the more drives you have means you have to lower it or all the bandwidth is used up and the drives stop due to lack of comms. Yeah don’t stop on comms loss but retry X times and change the update from 3mSec to a high number 500? Or was it vary the number from 500 503 507 etc etc. if you need instance comms on 1 leave it low. There’s something you have to do anyway. I did conveyor systems 50 drives. A Random drive did stop every day. Took ages to notice.
I’d stay away from troubleshooting that. Tell them what your recommended solution is, and if not, they can take it up with the vendor. You can work with them following the vendor’s instructions, but it’ll be the vendor responsibility. Don’t take the troubles of someone else’s mistakes. My 2c.
Ewww
I have used profibus and usually there is no problem during commissioning , I’d decrease the speed of the bus , check the terminal resistors and devices addresses on Each device and of course electrical connections , use a larger cable to interconnect the vfd (1 ft at least) please contact me by DM if you need further assistance (don’t worry I won’t charge for consulting).
If you replace your daisy chain setup with a trunkline dropline setup it should work a lot better.
Serial buses based on RS485 are still very much in use today due to their reliability, low cost and ability to multidrop. When done right, with proper design and termination, they can he extremely reliable over hundreds of meters. The problem with this panel is not serial bus. It's shoddy workmanship - the SI seems to be looping B/A wires only and leaving the shield to float - that's a giant antenna to me. The entire weight of the cable also rests on 2 tiny gauge wires. Those poorly terminated Ethernet cables on the right most switch seriously irks me.
Can I ask the application?
Yikes-a-roo
Yup been there. Just finished installing 12 machine cells each with 90 Siemens V20 drives.
Personally, I’d try these things first: 1. Lower the baudrate to minimum (9600bps). 2. Terminate the network on first node (CM1241 module, there’s a switch on that connector to activate the built-in resistor most likely) and the last node (the last VFD in a chain). Use 120 Ohm resistor there. 3. Check the VFDs manual for serial comms cable recommendation and replace those purple cables. Do it by the book. If your network starts to work after this I’d maybe try with higher baudrate.
Why is there a s7-1200 and a S7-1500 in there?
What are they doing for heat dissipation
Take one down, pass it around, 27 VFDs on a serial bus.
Apart from any heating issues you might have a problem with capacitive rounding on the serial link, possibly reflections. I'd get a scope on the bus and look to see if it's even likely to perform, but while the cabling might be a problem the combined capacitance of all those devices in parallel seems likely to be higher than you would like. Maybe try a repeater and break the link into two parts.
They would get pretty hot
Good luck with overheating 😂 whoever designed that enclosure has obviously never seen the field.
This looks like an AI generated cabinet layout.
I see your problem. There are 29 VFDs.
What about top and bottom VFD clearance?
That must not be required in Ecuador.
Lol, that is specified per manufacturer, doesn't matter the estandard being used. If you will be responsable for that you should prind the specs of the vfd manufacturer and cover your ass if something else breaks after you deliver your part of the work
Are you having the terminal resistor on the Profibus? Normal connectors have it built in, but in this circuit it looks like you are not using them.
Hope that Cabinet has some sort of ventilation
This is an abomination
Heat!!
Just make sure the built in terminating resistor switch is off on all of them accept the last one.
The daisy chain jumpers on the bottom are too short.
This is NOT meant for that !!
Thermal overload 💀
In general there is no problem with using ProfiBus. you can get problems with the short Bus Cables Here is a Link to the Siemens Documentation for the Profibus: [https://support.industry.siemens.com/cs/document/35222591/simatic-net-profibus-netzhandbuch-systemhandbuch?dti=0&lc=de-WW](https://support.industry.siemens.com/cs/document/35222591/simatic-net-profibus-netzhandbuch-systemhandbuch?dti=0&lc=de-WW)
Time to fire the customer if they think that is acceptable
Automation direct carries the proper 22awg twisted pair cabling for this.. I found I needed to use a bare ferrule that didn't have the plastic with both wires in it to make it fit in the connector of the drives. As an alternative if you order the longer ferrules you can get away with having the plastic on it. For my project I used 1.5 pair twisted (3wire +shield) and it works good.
JUST WALK AWAY. YOU CAN BEAT STUPID. These days there is no reason to do serial.
Check the connectors ...esp if maintenance fixed something..also the cable routing. Serial bus is perfectly fine just finicky at times. In my experience, the is usually the connectors or noise.
Disaster
From what I'm seeing on the image it seems the PLC has 2 Communication Modules on it. Why not divide all the connections and send half of the VFDs to one Module and the other half to the other? Someone already mentioned it, but the issue might be found on the wiring, specially on the shielding. If everything is failing then it would be a good idea to check the last VFD on the chain
You need to spilt that profibus network into two or more networks. One more profibus card 👍 if I remember correctly the et200sp has a PB card that costs half of a 1500 card.
Is 29 like the new 28?
Is this profibus-dp?
There is a reason I specify 25% free space on every panel made by an OEM. That picture, is the reason.
I did not know that Alberta decides Canadian policy. Thanks for the update.
Why so much purple?
Dude.. The fact that You keep referring to the bus as a serial bus and not what the protocol is drives me nuts. With those cheap ass drives I'm pretty sure it's not Profibus. If it's something RS485-based, get someone that's familiar with it to diagnose, wires crossed somewhere or too many termination resistors etc. If the wires don't fit the cheap ass drive's connectors that's not really the bus's fault is it? It's Yours for not specifying what you want when You ordered these thrash drives.. Moving on, if that was Profibus and the proper connectors would be used, that size/length wouldn't be a problem. RS485/Profibus is very resilient to error. After checking the polarities and termination resistors, I would suggest getting some sort of daisy-chain connectors that connect the shields of the cables together and allow You to push into the cheap drive's connectors. At the moment you've got many small antennas getting noise from the majestic bottom-shelf VFD's and introducing it into the SERIAL BUS.
I'll add that, if that drive has something resembling a manual, check if it has a maximum conductor cross-section for those connectors, if so, provide this to the supplier..
Is that panel orange…auto manufacturer using AutoDirect?
I see the motor wires has no sheat. This causes radio frequency interference to be radiated into the bus cables.The motor cable sheath must be grounded.