Controllogix RS-232 and GE Cable

[10dulkar]

I am trying to use the RS-232 port (Channel 0) on my Controllogix processor to communicate with a device. I am trying to use the AWT command to send and ABL/ARL commands to monitor my port and receive the reply. Not getting to far with it.

It seems to be sending the command just fine but doesnt seem to come back with a reply from my RS-232 device. Obviously it could be the device but I dont think so. Anything I should be doing to first "enable" or configure the port other than baud rate etc.

Also I have an IC200CBL500A cable from GE I think. Does anyone have a pinout for this cable. Cant seem to find it on the GE Site.

Thanks for your help!

 

[PhilipW]

The best generic advice for diagnosing RS232 problems is to use Hyperterminal on your PC to display the data flow.

Once you have established with Hyperterminal that all the baud rates, cables and data formats are right then getting the PLC and remote device to talk is usually pretty easy.

 

[10dulkar]

Please help!!! I think I am going to have less hair by the end of this.

I can communicate between my device and my PC and I can communicate between the the PLC and PC but I cannot get the device to work with the PLC.

I am using the AWT command in Logix 5000 to write an ASCII string to the device. The device never responds as if it never got the command. If I hook Hyperterminal (HT) and send a command through HT, device responds fine. But not when the AWT command sends the string.

What am I missing? Do I need any conversions? Setup?

Any help appreciated.

Thanks.

 

[Eric Nelson]

I think you missed Philip's point. Instead of using hyperterminal to talk TO the device (which you've proven works), use hyperterm to listen FROM the PLC. IOW, let hyperterminal act as 'the device', and watch what the PLC sends.

beerchug

-Eric

 

[10dulkar]

I did try that. The HT confirms the correct string receipt from the PLC but the device acts as if nothing was received.

I have tried swapping cables, baud rate, parity changes. Just about everything I can think of.

The only 2 things I can think of that might be causing this is signal grounding of the device w.r.t plc and byte swap issues. Any thoughts on how can I check these 2 things?

In the HT I didnt see any byte swap settings nor in the PLC so I am assuming what I see in HT is what is received by the device.

I cannot believe this is taking so long. The HSC card was easier to setup than this.

Help!

 

[PhilipW]

OK. Now I assume you ahave used HT to send the same data string to the device. ie can you get the device to respond to HT as if it were the PLC.

I understand your pain. Getting these kinds of things to work can be real bald-making fast.

The problem is not the PLC..something is being overlooked.

 

[Ken Roach]

Much of my hair has grown back since I invested a little money in two lovely tools that I can't do without.

The first is a two-port RS-232 PCMCIA card from Quatech called the DSP-100. These serve as COM4 and COM5 on my computer.

The second is a serial data capture program from HHD Software, called simply "Serial Monitor".

These are a little pricey to solve just one problem with; $180 for the card, $80 for the software. But I've solved a generous handful of problems with it and, more importantly, relieved plenty of stress.

The two-port card (I have also used two USB/RS232 Keyspan interfaces) allows the software to be placed between two asynchronous RS-232 devices, sending data from one to the other and displaying it in the process. It's easier and cheaper than any other "serial spy" I've found, and I've tried lots.

You're going to need this sort of tool if you want to really troubleshoot ASCII communications without guessing.

You could post your RSLogix 5000 file; maybe someone wants to take on the challenge of figuring out your Channel 0 settings and AWT configuration.

 

[Eric Nelson]

Another thought...

Are you also sending any necessary control characters? Things like carriage return <CR> sometimes get overlooked. When you send from hyperterm to 'the device', YOU hit return, which adds the carriage return. The PLC will not automatically do this. The control characters need to be embedded in the string.

By the way, what it 'the device' you're trying to talk to?...

beerchug

-Eric

 

[10dulkar]

After numerous hours into this finally got it working... both through the JDC Gateway and the Channel 0. Finally!!! And both are simplest of problems!

First off thanks a lot to all for your help!

Anyways I was trying to communicate with a Keyence Laser Controller through my CLgx 5555 processor.

First I tried the 1782-JDC converter from WRC. This device was appending an extra <cr> to the commands. Reason: The TX size setup in devicenet. I had it configured for longer command strings. As it turns out if you send a very short command string, it will just append a <cr> to end of the command. I reduce the size and it works!

Since I couldnt get the JDC to work earlier, I tried going directly through channel 0. As it turns out (and as Eric pointed out) the AWT command sends characters upto the <cr> in the string and not the <cr>. So I tried the AWA command and setup the Channel 0 to append an extra <cr> and that also works now!

I think the 2 tools recommended by Ken sound interesting. I think I will invest in that. The hidden chars like <cr> and linefeed dont show up in the HT software and this can waste a lot of time as I just discovered.

Anyhow thanks again to all of you for your tremendous help. Lets hope the rest of this will go smoothly.

BTW if anyone is using a Cutler Hammer VFD, well watch for RFI noise on your Ethernet line if its anywhere close (close = running 5 feet from the enclosure). Another thing I lost sleep over recently!

Happy Holidays!!!