Communication error between younger PLC guy and older PLC

cjfugal

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Join Date
Apr 2021
Location
american fork utah
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Howdy,

I'm trying to connect to an SLC 5/04 using an old Toughbook running windows XP over the RS-232 port.
Cable 1761-CBL-PM02
RSLinx Classic lite
RS-232 DF1 Driver
Com1

I have tried 2 processors, in each case once the processor is powered on I get a blinking red FLT light and a slower blinking DH+ or RS232 light, from the manual I gather that this means it cant find anything to talk to.

Auto configure driver in RSLinx returns either:
"unable to find baud rate and parity" or "unable to verify settings due to packet timeout"

I'm admittedly more familiar with ethernet connections but I'm not altogether foreign to serial, is there something I'm missing?
Help would be greatly appreciated.
 
Ooh, it's been a while but I believe that port on the 5/04 is DH+, you need a very special, expensive adapter to connect via that port. These days, it is the 1784-U2DHP

Get a USB-Serial adapter and a null modem cable, like the 1747-CP3 and connect to the RS-232 port, assuming that it is at its default DF1 configuration.
 
Based on the cable he mentioned, he is connecting USB on his PC to the serial port on the 5/04.

My worry here is if Windows XP is recognizing your USB to Serial converter cable. I haven't tried these on XP before. The cut sheet on this cable mentions no drivers needed for Windows 7 and higher.

Before we hassle with RSLinx, lets see if XP is recognizing it, and what COM port it is using.

In XP go to the Control Panel. From the Classic View double-click on System, then click the Hardware tab and click on the Device Manager button. Expand ports to see the COM ports available. USB converter devices can use any unused COM port number. I frequently see them using COM5. Verify the port setting. I don't have one here to dig deeper, but typically you can open the properties for the device and show the COM port and baud settings.

Once you know for certain that the COM port is recognized in XP and the COM port it is using, then go back to RSLinx and make whatever changes are necessary for the driver.

OG

EDIT: The cable you mention has a round style connector that was used on the MicroLogix. The SLC 5/04 has a D-style serial port. Are you using an adapter to make this physical connection?
 
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Ooh, it's been a while but I believe that port on the 5/04 is DH+, you need a very special, expensive adapter to connect via that port. These days, it is the 1784-U2DHP

Get a USB-Serial adapter and a null modem cable, like the 1747-CP3 and connect to the RS-232 port, assuming that it is at its default DF1 configuration.

OP said he was trying to connect via the RS-232 port: "I'm trying to connect to an SLC 5/04 using an old Toughbook running windows XP over the RS-232 port."



Is the RS-232 light blinking happening with nothing connected? If it is configured for DF1 it should have a relatively fast blink when there is traffic and nothing otherwise. A slow blink with nothing connected is likely to mean it is configured for DH-485, in which case you'll need a 1747-UIC to communicate with it.
 
Is the RS-232 light blinking happening with nothing connected? If it is configured for DF1 it should have a relatively fast blink when there is traffic and nothing otherwise. A slow blink with nothing connected is likely to mean it is configured for DH-485, in which case you'll need a 1747-UIC to communicate with it.

Good point. If it is configured for RS-232 then when nothing is connected it should be off. But when you try Auto-Configure it might flash slowly for a few moments then turn off. But if it is configured for DH485 it will every few seconds.

OG
 
OP didn't mention USB adopter and even the newer Toughbook does have a real serial port.

Typically, auto-config on the DF1 driver just fails but I do not recall seeing these two erros before. I would try to clear the memory (search) on the processor and manually set the comm setting to default.
 
OP said he was trying to connect via the RS-232 port: "I'm trying to connect to an SLC 5/04 using an old Toughbook running windows XP over the RS-232 port."

I understood that, but he said that he was using a PM02 cable, which would mean that he is not actually connecting to the 9 pin RS-232 port, but instead, was connecting to the round DH+ port. Unless I'm losing my mind, which is always a possibility.
 
Operaghost said:
The cable you mention has a round style connector that was used on the MicroLogix. The SLC 5/04 has a D-style serial port. Are you using an adapter to make this physical connection?

The processor card I have has the round "Straight-D connector" so it physically plugs in fine, and I am using a real serial port on the laptop.

harryting said:
I would try to clear the memory (search) on the processor and manually set the comm setting to default.

Didn't see that in the manual, do you clear the memory on the card itself or from an external device?

plvlce said:
Is the RS-232 light blinking happening with nothing connected? If it is configured for DF1 it should have a relatively fast blink when there is traffic and nothing otherwise. A slow blink with nothing connected is likely to mean it is configured for DH-485, in which case you'll need a 1747-UIC to communicate with it.

its a slow blink, I now have both DH+ and RS232 lights blinking. RS232 with a longer, slower blink
 
I understood that, but he said that he was using a PM02 cable, which would mean that he is not actually connecting to the 9 pin RS-232 port, but instead, was connecting to the round DH+ port. Unless I'm losing my mind, which is always a possibility.

I'm about to lose mine, I thought DH+ was that 3 pin thing above the round port that works like a preliminary version of profibus?
 
I'm about to lose mine, I thought DH+ was that 3 pin thing above the round port that works like a preliminary version of profibus?

I believe they are both DH+. The round one would be for connecting for programming purposes, the 3 pin would be for networking multiple devices.
 
Might be a good time to think about upgrading to a 5/05 or you know a current PLC.

I don't like the upgrade path Rockwell provides for that platform though. (I'd rip it out and start fresh)
 
Might be a good time to think about upgrading to a 5/05 or you know a current PLC.

I don't like the upgrade path Rockwell provides for that platform though. (I'd rip it out and start fresh)

I mean, i'm not against that idea, but this place is budgeting/scheduling an upgrade for one of its PLC 5 systems at the end of this year (Yes ONE of, we have 3 more large PLC 5 systems), the SLC 500's will probably have to wait a bit.
 
The 5/04 has three connections.

3-pin DH+ port (top)
Mini-din style round DH+ port (middle)
9-pin D type Serial port (bottom)

The round port and the 3-pin port are paralleled. The network cable plugs into the top connection and your laptop plugs into the mini-din connector. They give two connections to the same DH+ network. This is not serial, and it requires a DH+ interface device to plug into your laptop (USB, PCMCIA, ISA PCI). The USB interface is still available, but it is very expensive. It has a USB cable for your laptop and the round DH+ connector for the PLC.

The bottom connection is the 9-pin D-style RS-232 connector and requires a null modem serial cable. If your laptop has a serial port, this is what you want to use.

OG
 
I believe they are both DH+. The round one would be for connecting for programming purposes, the 3 pin would be for networking multiple devices.

I believe this is correct. You are quite right that the cable number given would connect to that port, mea culpa.

Since it sounds like the RS-232 is indeed configured for DH-485, then resetting to factory defaults is likely to be your best bet (assuming you don't care about any program currently on the processor), as that should reset the RS-232 port to DF1.

See here for instructions on how to do so -- in short, disconnect the battery and then short the VBB and GND connections on the controller board to drain the capacitor.
 
The 5/04 has three connections.

3-pin DH+ port (top)
Mini-din style round DH+ port (middle)
9-pin D type Serial port (bottom)

The round port and the 3-pin port are paralleled. The network cable plugs into the top connection and your laptop plugs into the mini-din connector. They give two connections to the same DH+ network. This is not serial, and it requires a DH+ interface device to plug into your laptop (USB, PCMCIA, ISA PCI). The USB interface is still available, but it is very expensive. It has a USB cable for your laptop and the round DH+ connector for the PLC.

The bottom connection is the 9-pin D-style RS-232 connector and requires a null modem serial cable. If your laptop has a serial port, this is what you want to use.

OG

Ok that clears up some questions for me, thank you.

OK, we got it talking (Finally found a backup that was in this rack), not over serial, if I had to guess why its because the processor is configured for a different communication protocol, I'm still not sure how you would change that but for anyone else that runs into this issue, this is what worked here:

Edit: Further replies explain resetting, thanks guys

Cable 1784-PCM5/B (I didn't know this thing existed, partner knew about it. it plugs into a magic removable port on the right side of the laptop, haven't tried it but I think you could use it with an anaconda)
Adapter from round port to 9 pin
RSLinx driver AB_KT-1 no configuration necessary
 
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