Communication Issues with SLC 5/02

[Galador]

Hey everyone. This is my first post here. I am newer to the automation world and have had an issue while trying to communicate with an SLC 5/02. I don't have the exact model, but I attached a photo of what it looks like exactly.

Every other PLC I have communicated with has some sort of serial port I can plug into and configure everything in RSLinx. The problem is I am trying to connect into this SLC 5/02 through the only port I can find on it which appear to be an RJ45.

My laptop only has USB ports on it so I used a cat5e ethernet cable to plug into the plc, from there I used a converter to go to a 1747-CP3 cable and from that finally to a DB9 to USB (I know, not ideal). Using this method, I was able to get the processor to show up in Linx (Couldnt auto-configure) BUT it kept switching the type of processor (Showed PLC 2/30, Mini PLC, and a bunch of other things) It also occasionally had a red X over it. I assume this means that the connection in general was bad (probably due to my wacky cable configuration). But I am not sure what else I could use to connect to it.

Does anyone have any ideas on how I might communicate with it? I have tried a bunch of different combinations, but nothing seems to work.

*I also have a 1747-UIC. Tried plugging into the DB9 port as well as the RJ45 port on that thing and nothing worked with it. Not sure if you can even use it for those models of SLCs.

 

[Jim3846]

SLC 5/01 and SLC 5/02 DH-485 protocol
DH-485 channel offers:
• configurable isolation via the 1747-AIC or 1761-NET-AIC
interfaces.
• maximum network length of 1219 m (4000 ft).
• RS-485 electrical specifications.
• Belden 9842 or Belden 3106A cable connection between nodes
(daisy-chain connection

 

[OkiePC]

Hopefully you didn't smoke your Ethernet adapter since pin 1 of that DH485 port has 24VDC present. That connector is RJ45 which nowadays is common for Ethernet, but electrically it is a customized RS485 electrically and uses D485 protocol.

Buy one of these:
https://www.plccable.com/allen-bradley-1747-uic-usb-to-dh485/

 

[plvlce]

To my knowledge 5/02 only has DH-485 communication.

A 1747-UIC is the preferred method of communicating for programming imo. Plug the USB connection into your computer, then a standard ethernet cable from the UIC adapter into the RJ45 port on the processor. (Do NOT plug directly from your PCs ethernet port into the processor...) Verify the switch on the adapter is towards the RJ-45 port rather than the DB9 connector on the end.

Using Device Manager, identify which serial port Windows has set the adapter to use and create your driver in RSLinx using that port. I prefer to use the DH485 UIC Devices driver, but have used others in the past successfully.

 

[Galador]

Hopefully you didn't smoke your Ethernet adapter since pin 1 of that DH485 port has 24VDC present. That connector is RJ45 which nowadays is common for Ethernet, but electrically it is a customized RS485 electrically and uses D485 protocol.

Buy one of these:
https://www.plccable.com/allen-bradley-1747-uic-usb-to-dh485/

I have one of the official AB adapters of the product you showed. I used a Cat5e ethernet cable to plug into it (1747-UIC) not my actual laptops port. I'll check to make sure that the adapter I used is still okay.
Would the pinout of a cat5e cable not work to transmit data from the PLC to the UIC? As in would you know if it wouldnt work to transmit with the DH485 protocol?

 

[Galador]

I did this originally using a Cat5e cable but it wouldnt communicate at all(When using the UIC). I am wondering if the Cat 5e's pinout isnt able to work with the DH485 protocol.

 

[Ken Roach]

Okay, good, you've taken a step back. Welcome to the PLCTalk forum community !

The SLC-5/02 and other SLC-500 controllers with a DH485 jack on them existed before RJ45 was the default for Ethernet. They are NOT ETHERNET.

The SLC-5/02 port supplies +24V power for interface devices like the old 1747-PIC and the 1747-AIC. That's one reason you never want to plug it into an Ethernet jack; it won't just not work, it will often let the smoke out of the Ethernet device.

The installation instructions for the 1747-UIC tells you to use a 1747-C13 cable to connect the UIC to an SLC-5/00, 01, 02, or 03 controller.

What the instructions *should* say is "the 1747-C13 cable is not an Ethernet cable, and you should not use EIA/TIA 568A or 568B cables in place of it".

The pinout of the 1747-C13 is a "straight through" connection, omitting pins 3 and 6.

 

[Galador]

Thanks! Shouldnt a straight through ethernet cable be able to act as a C13 or would those two omitted pins cause an issue? For some reason while using the 1747-UIC I was never actually able to get any form of communication through the RJ45 port on it. (The DB9 port on the bottom did work for other PLCs). I also did ensure that I was switched onto the right port on the UIC.

 

[Ken Roach]

A more thorough statement in the manual might be:

While EIA/TIA 568A and 568B pinouts are straight-through like the 1747-C13, the presence of +24v on Pin 3 may cause damage to some non-isolated devices, and the connection of a conductor instead of one side of the shield drain conductor on Pin 6 may cause interference or ground loops on some systems.

An "Ethernet Crossover" cable with different pinout standards on each end will mis-connect the signal conductors and must not be used.

I can't say for sure what went on in your system; the physically inventive connection from RJ45 to RS-232 shouldn't have worked at all, even to display garbled identity information. It should not have, but might have, caused a short to ground and damaged the SLC-5/02 power supply section.

I used to put "NOT ETHERNET" labels on SLC-5/01-2-3 controllers just for the future users who didn't remember back in the day.

Some (but very few) DH485 networks are set for 9600 bit per second; virtually all use 19200.

One handy visual diagnostic for DH485 ports on SLC controllers is the if the port is physically unplugged, the LED will blink at about 1 Hz. That's even true of the physical RS-232 ports on SLC-5/03-4-5 and MicroLogix controllers when they're configured for DH485 logical protocol.

Once a device is plugged in and the DH485 token-passing protocol gets going, the LED switches to solid green and should not blink, "flash", or "flicker".

That's dissimilar to DF1 protocol, or ASCII, which "flickers" the LED every time the port transmits.

DH485 port status LEDs on some devices that aren't SLC-5/0x controllers will also "flicker" as data is transmitted (I think the UIC does that) but the ports on the controller are built to indicate their network token passing status, not the actual transmission of each packet that goes through.

Again, welcome the PLCTalk forum community. Those old SLC's were durable workhorses for decades but it can be a pain dealing with legacy networks and cables.

 

[Galador]

Wow. I really appreciate all of this info. It's helped me look into the issue a lot more in depth than I could find from other sources.

That being said:

1. I will likely Label the SLC just like you did. That is a very good idea for future users.
2. I'm going to look into purchasing the C13 cable we were talking about or creating my own by omitting the pins. (I have the materials to create ethernet cables so it should be a matter of removing the proper wires and wiring it correctly).
3. When using the RS232 port for an SLC 5/04 I did connect and the UIC's LED did flicker while transmitting data like you said.

All in all, I'm glad to have some stuff to test out next week to see if I can get into these 5/02s. Also, yes, these SLCs has been a bit of a pain to connect to properly (even between the same model I have had to switch cables up). Either way though, I feel like I have learned a lot through it so I guess that's a plus. Thanks again for the help. I will drop an update in the thread on what ends up working.

 

[Galador]

I am fairly certain that the C13 does have pin 6 connected. I am having trouble finding where you found that information. Pin 3 seems like its not connected. Regardless, removing the wire from 3 and 6 resulted in no change.

 

[Mickey]

I am fairly certain that the C13 does have pin 6 connected. I am having trouble finding where you found that information. Pin 3 seems like its not connected. Regardless, removing the wire from 3 and 6 resulted in no change.

Here is another source from a knowledgebase when they were free..

Ans another issue..

There is one potential pitfall: the default baud rate for DH485 is 19200, and this is what you will find most of the time. However, it is possible to configure it in the PLC settings to be 1200, 2400, or 9600 baud at as well.

The 1747-UIC adapter only supports 19200 baud out of the box. If you have an original A-B unit, it is possible to change to the baud rate to 9600 by following the steps in this Rockwell knowledgebase document (requires creating a free account and logging in).

 

[alan_505]

I found a software package for the 1747-UIC on the RA knowledgebase that lets you set the baud rate to 9600, it works well but you need to set it each time to 9600, as it defaults back to 19200.

 

[geniusintraining]

I found a software package for the 1747-UIC on the RA knowledgebase that lets you set the baud rate to 9600, it works well but you need to set it each time to 9600, as it defaults back to 19200.

Rockwell Technote:
ID: IN5020 | Access Levels: Everyone
Connecting to a DH-485 Network at 9600 Baud with the 1747-UIC

https://rockwellautomation.custhelp.com/app/answers/answer_view/a_id/493842