Trouble with getting online and uploading program from Compactlogix L31

[darwil93]

I'm wanting to upload the program from a CompactLogix L31 Controller. I'm using a generic (non Allen Bradley) "C2G brand" usb -->rs232 cable coming directly off of my laptop because I don't have a serial port out. The rs232 side of the C2G cable is a "pin out" or male end, and as you can see in the attached picture, the serial port at Channel 1 on the controller is also male. I'm using a generic (non-Allen Bradley) null modem (female-->female) cable to complete the connection. Ultimately, I'm not seeing the controller on linx. But that's a result of me not being able to configure the driver. When I try to auto configure this driver, Linx gives me an error saying, "Unable to verify settings due to a NAK!"

I have used the -USB to serial- cable with some micrologix controllers and have successfully gone online and uploaded programs from them. But the secondary cable that came after the -USB to serial- cable was an Allen Bradley 1761-CBL-PM02 serial cable.

btw, the rs232 cable going into channel 0 is for the HMI on the machine. A pv600

1. How do I get online and upload the program from the controller?

2. What does NAK mean?

 

[tarik1978]

you should use 1756-CP3 or 1747-CP3 serial cable.
Here's a good tutorial on how to connect to CompactLogix using serial:
https://theautomationblog.com/how-to-connect-to-a-compactlogix-using-serial/

 

[Ken Roach]

Welcome to the PLCTalk forum community !

Many inexpensive USB/RS232 interfaces don't support the rapid changes to baud rate and serial framing that the "Autoconfigure" feature of RSLinx Classic's DF1 Full Duplex driver.

Try setting up that driver manually:

Device Type Logix 5550/CompactLogix
DF1 Full Duplex, no handshaking
19200/8/N/1
BCC Error Checking

Double-check that your serial cable really swaps Pins 2 and 3 and carries Pin 5 straight through. DF1 doesn't require any of the handshake pins to be jumpered.

It's possible that the top port is set up for ASCII or DH485 disabled, I guess.

"NAK" means "Negative Acknowledge". That message tends to suggest that the controller sent back a rejection of a packet from RSLinx, not that it timed out. But I'm not 100% sure.

 

[Ken Roach]

Reaching back into the memory banks:

This model of CompactLogix has a "DCOMM" button hidden behind that little hole by the Channel 0 status LED, which allows you to override the Channel 0 (the one with the cable in it) serial configuration and return it temporarily to the default DF1 Full Duplex 19200 BCC settings.

If you press and hold the DCOMM button, the "DCH0" LED at the top will come on. Press and hold again, and DCH0 turns off and the controller is back to whatever configuration the user program has for that port.

My guess is that the Channel 0 port is set up for Data Highway 485, connected to a PanelView 600 terminal that uses DH485 protocol.

I can't tell for sure from a still photo, but that Ch. 0 status LED looks steady green, which indicates the DH485 token passing is going on. If it were DF1 Full Duplex, the LED would flicker rapidly as packets are transmitted, and generally that looks dim in a still photo.

If I couldn't get Channel 1 working, my next step would be to connect to Channel 0, press the DCOMM button so I'm sure the port is in DF1 Full Duplex mode, and use the DF1 Full Duplex driver in RSLinx Classic.

 

[darwil93]

Welcome to the PLCTalk forum community !

Many inexpensive USB/RS232 interfaces don't support the rapid changes to baud rate and serial framing that the "Autoconfigure" feature of RSLinx Classic's DF1 Full Duplex driver.

Try setting up that driver manually:

Device Type Logix 5550/CompactLogix
DF1 Full Duplex, no handshaking
19200/8/N/1
BCC Error Checking

Double-check that your serial cable really swaps Pins 2 and 3 and carries Pin 5 straight through. DF1 doesn't require any of the handshake pins to be jumpered.

It's possible that the top port is set up for ASCII or DH485 disabled, I guess.

"NAK" means "Negative Acknowledge". That message tends to suggest that the controller sent back a rejection of a packet from RSLinx, not that it timed out. But I'm not 100% sure.

So I ended up sticking with both generic cables but manually configuring the driver with those parameters you gave, and went to working fine! Got it to upload/get online.
Funny thing is.... I manually set all those parameters in Linx for the driver I was using before I even connected a cable. When I tried it manually in Channel 1 first, it still didn’t like it.
I switched to Channel 0; but just for kicks I hit auto configure just to see what would happen, and it did it successfully. So with the driver set I went ahead and uploaded from it from Channel 0.
I didn’t touch any configuration settings for either port once I was in the program. But once
I plugged the HMI back up, I tried going into Channel 1 again, and that time it worked. Went online with it just fine.

Thanks for everything! All your info was extremely helpful.