SCL 500 5/04 Comm.error 00000001

[ALCARA_PLC]

Hi all,

This is my first post; I am new to PLC Controls stuff and English is not my native language, so I apologize in advance if something is not as clear as I would wish.

I am working on an area of my plant where there are 4 PLC for 4 different machines (A to D). These are all connected through DH+. I could usually go online with no problems, but around a month ago the communication started having some issues with A and B specifically. Every time I wanted to connect I had to try to go online 4 times or so, until it finally went online.

Last week, I was working on some changes on B and C, and I lost connection due to communication error, and when I tried to connect again I couldn't and it showed several errors, like 'that processor is not a 500' or 'corrupted program'.

I thought there could be a problem for something I didn't save, but the machines are still running until now, and the problem is also happening with A and D.

The way they are connected on the DH+ is like this (and sorry again for not be that proficient explaining this):
Workstation>
Controller>
Backplane>
Slot 1>
Channel A>
Node 1>
Machine A
Channel B>
Node 1>
Machine B
Slot 2>
Channel A>
Node 1>
Machine C
Channel B>
Node 1>
Machine D

There are other machines from other areas connected to this controller, even on the same channels, but I was wondering if there cold be a way only node 1 of both channels on each slot is damaged. IDK.

Well, the issue doesn't end there -_- ... now, when I thought I could connect with two PLC's (B and C), it shows the file is not the same as the one I want to go online with, but when I choose to create a new file, it starts showing 'communication error' while loading the file. x.x

I will appreciate any guidance or tip about this.

I know in advance these PLC are old as S, but I am working on replacing them 1 at the time. But first I need to figure out what is going on now.

 

[OkiePC]

Two things:
1. How many unique nodes are on each DH+ network? I think from your description there is at least one Controllogix Gateway involved. When you get more than a half dozen or so nodes in total, expect delays, and they are compounded if there are messages between machines hogging up the bandwidth.

2. Check your RSLinx Communication settings. There will be a post on this forum that shows some settings that may help...I can't remember if they only apply to Ethernet or if they also apply to DH+. I will dig for a link and post an edit shortly.

Welcome to the forum. Your English is fine, by the way.

EDIT: See this thread about the RSLinx comms options:
https://www.plctalk.net/qanda/showthread.php?p=907588

 

[Ken Roach]

DH+ station numbers must be unique on each physical DH+ network, and the default station number of an SLC-5/04 is Node 1.

So be certain that there are not two controllers connected to the network and configured as Node 1.

It's also possible that you have some degraded wiring or signal interference. Inspect each screw-terminal termination, and be sure there are just 2 terminating resistors at the far ends of each daisy-chain.

DH+ can run at 230.4 kb/s with 82 ohm terminators, or at 57.6 kb/s with 150 ohm terminators. Your DHRIO configuration will tell you what data rate the network is running at.

Check to be sure that nobody has changed an HMI, or connected a bunch of RSLinx computers bridging through this arrangement to browse the DH+ networks.

And the DHRIO (and the Comms Diagnostic Data File in the SLC-5/04 if one is defined) has some physical link layer statistics you can examine to see if there are bad packets and retries.

 

[ALCARA_PLC]

Two things:
1. How many unique nodes are on each DH+ network? I think from your description there is at least one Controllogix Gateway involved. When you get more than a half dozen or so nodes in total, expect delays, and they are compounded if there are messages between machines hogging up the bandwidth.

2. Check your RSLinx Communication settings. There will be a post on this forum that shows some settings that may help...I can't remember if they only apply to Ethernet or if they also apply to DH+. I will dig for a link and post an edit shortly.

Welcome to the forum. Your English is fine, by the way.

EDIT: See this thread about the RSLinx comms options:
https://www.plctalk.net/qanda/showthread.php?p=907588

I appreciate you dedicated a time to help me Okie.


According with what you listed, this are my comments:

1. I just doublecheck with my IP master file in plant, and there are 40 individual nodes being used on the Data Highway, assigned to 3 different slots and their respective channels (A and B). We are using a Data Collecting Software connected through the DH+, that's why I always stop it for a while until I can go online (sorry for didn't mention that before). Due to this last and added to the fact that these are the only equipment having this specific problem at the moment, is why I didn't consider this was an issue or root cause.

2. Well, not sure if RSL could be the issue, because as mentioned I have no issue connecting with any other equipment connected to this DH+ controller's backplane. I will doublecheck though. Specially any configuration on these 4 PLC's not matching the controller or RSL settings. Also, I am not sure if something could've changed by itself during my logics modifications, but that was only on 2 out of 4 machines, not on all of them that have the problem now x.x. I have read there could be a problem caused by a outage, but that would affect the controller and all the nodes on it, not like this nodes '1' from different channels specifically. It's really weird.

And, for that link, it looks pretty helpful. However, this is for online editing, and the funny part is that I had this issue also XD, but could figure out the step listed on one of the Rockwell links from the thread.


BTW. Yesterday afternoon I went to the PLC's cabinets to make some physical inspections, and some guidance from the controllers LED status, but they look good. The 'Run' and 'DH485' LED were the only ones ON. Buuuuut... On all these PLC's there are 'Weigh Scale' modules on location 9 and 10 (if that matters), and they looked to be faulty. On A, B and C 'Fault' LED was ON and 'Comm' LED was flashing. On D both of these LED were flashing. I am not sure if this could affect the connectivity of the controller, but I just mention it just in case. The machines were running apparently fine, and I can't confirm or deny these LED were like this before.

again...

 

[ALCARA_PLC]

DH+ station numbers must be unique on each physical DH+ network, and the default station number of an SLC-5/04 is Node 1.

So be certain that there are not two controllers connected to the network and configured as Node 1.

It's also possible that you have some degraded wiring or signal interference. Inspect each screw-terminal termination, and be sure there are just 2 terminating resistors at the far ends of each daisy-chain.

DH+ can run at 230.4 kb/s with 82 ohm terminators, or at 57.6 kb/s with 150 ohm terminators. Your DHRIO configuration will tell you what data rate the network is running at.

Check to be sure that nobody has changed an HMI, or connected a bunch of RSLinx computers bridging through this arrangement to browse the DH+ networks.

And the DHRIO (and the Comms Diagnostic Data File in the SLC-5/04 if one is defined) has some physical link layer statistics you can examine to see if there are bad packets and retries.

Hey, Ken.

Thanks for your contribution.

From what you said;

There should be no one else messing with the programs or connections in that area but me. Despite that, I will consider that option as a 'could be' and will doublecheck, of course.

I have for sure that there are some people with access and some knowledge to connect to the equipment, but the problem started getting worst when I was working on them. So, that's why I am not sure if I screwed it up or something, even when I was working on 2 from 4 of these PLC's.

From the wiring, that makes some sense. We had some issues on one machine's HMI's, that was lost signal twice (because there are two HMI's connected to the same DH+ port from the PLC in parallel, they are basically the same HMI, not Master and Slave; we have it that way because of the distance for the operators). I personally verified the tightness of the wiring and terminal block and didn't find something wrong. However, after that this problem didn't happen again.

The resistance and DHRIO stuff sounds really interesting and new for me, I will definitively take a look to that.

BTW. Yesterday afternoon I went to the PLC's cabinets to make some physical inspections, and some guidance from the controllers LED status, but they look good. The 'Run' and 'DH485' LED were the only ones ON. Buuuuut... On all these PLC's there are 'Weigh Scale' modules on location 9 and 10 (if that matters), and they looked to be faulty. On A, B and C 'Fault' LED was ON and 'Comm' LED was flashing. On D both of these LED were flashing. I am not sure if this could affect the connectivity of the controller, but I just mention it just in case. The machines were running apparently fine, and I can't confirm or deny these LED were like this before.

again...