MODICON Remote IO

[proisy]

We have lot of problems with MODICON RIO :
- does somebody have the same problems ?
- does somebody have solutions ?

Schneider don't arrive to solve it.

 

[krkautomation]

Hmmmm... I think you'll have to be a bit more concise if you want any help........

http://www.krkautomation.com

 

[proisy]

We use MODICON QUANTUM PLC with Remote IO for extended back planes (using CRA + CRP cards and coaxial cable).
We often have breakdown of the PLC because of communication failure between the CPU and the extended racks.
Since we discover this, we try to find the reason, then we frequently read the satus counter of these communications and some time the counters increase. In this case, if possible, we stop the PLC and we scrape the copper wire, we restart the PLC and the counter don't continue to increase.

For us, the problem is with the connexion and we searched for an other solution for several years without succes.
We asked also to Schneider, but they told us that they have not this problem with other customers !

If I post this in this forum, its for 2 reason :
1/ find a solution (it is the best for me)
2/ find other enduser who have the same problem and be able to have a stronger position related to Schneider

 

[krkautomation]

Every time we have had problems with these installations, it has been the RG6 & RG11 coax crimp connectors that have been the cause.

We tried a few combinations of different manufacturers cable/connector but still found that if they were disturbed, we could lose the drop ..we eventually 'solved' this by immediately after crimping and testing the connection, installing a short length of adhesive lined heatshrink sleeving overlapping the back of each connector onto the cable to hold the connector firmly in place.

(I'm taking it as given that you have followed the installation guide to the letter)

http://www.krkautomation.com

 

[fsmyth]

What is the connector type here?
If BNC, it needs to be relatively strain-free (no side-loads).
The tip about heatshrink is a good one; I would extend it to
a second layer and/or sleeve if exposed. BNC is not the best
choice for rough environments. Use right-angle connectors or
adaptors for tight quarters - NEVER bend the cable at the
connector. Replace with TNC or SMC if possible. Any screw-on.
If you have a humid environment, fill the connector with
silicone gel. A properly made-up connector, filled if
necessary, should be servicable for years.
The manufacturer is correct. Most folks don't have these
connector problems. If they do, they will finally learn.

<als>

 

[krkautomation]

They are f-type to match the Quantum RIO drop/head modules and bus taps.

Right-angle adaptors are supplied with the PLC modules for strain relief & to enable you to close the front covers.

Initially we purchased everything - trunk & drop cable, connectors, tooling from Modicon/Schneider using the part numbers in the RIO installation guide but they just sent a mixed-bag of third party components. The RG11 trunk cable connectors were the worst, they were just a 'twist on' fit rather than crimped and were too big for the O.D of the coax supplied. When we eventually got fed up with the lack of tech support response, we sorted different cable & connectors ourselves for subsequent jobs.

(As a footnote, after a couple of machines using this stuff the client changed their site standard from Modicon to Siemens although apparently it was not directly attributed to this issue)

http://www.krkautomation.com

 

[fsmyth]

Ah. Now I begin to understand. My sympathies.
Apparently, the current generation does not even know that
solder-type connectors exist, much less how to install one.

To the OP:
Tell the upper turkies that you need some F-to-BNC adaptors,
and re-terminate ALL cabling. Get a GOOD crimping tool, and
use at least half-way decent connectors. If you use anywhere
close to decent cable, your problems will evaporate.
If you cannot sell using BNC, the rest still applies.
Use the cheap crap for home T.V. and the media room.

<als>

 

[drhano]

we ran into the same problem up here in canada. It turns out that the remote io coax cable was being ran to close to a power line. 600 volts i believe. to get rid of the communication problem without re-routing our cable we installed fiber optics communications and it hasnt skipped a beat ever since. fiber optics truly is a the way of the future, what a fantastic way of communicating

 

[modiconbob]

I was employed by Modicon for 20 years. I have worked on just about every type of system/application out there.
There are certain rules that as the system gets larger, both in footage and in drop count, that you MUST adhear to.
Drop cable and trunk cable type, minimim and maximim lengths, tap type, splitter use, balancing etc. True that most issues are cable/connector related. I have spec'ed for Modicon a set of RG-6 and RG-11 connectors that fit their ONLY specified cables properly. As for BNC connectors, there are very few folks that can install one correctly. Use the F's. If necessary use adaptors, although the increased "plumbing" creates it's own problems. Best to update your equipment to newest revs which all have F's.
When I left MOdicon, the expertise left with me.

 

[proisy]

You tell "Use the F's"! English is not my mother tongue, and I don't understand this, could you explain ?

 

[modiconbob]

I mean to say use the "F" type connectors instead of the BNC type.

 

[pc45]

Our problems with RIO drops are similiar to the ones listed. We have had problems with noise due to 480v power near the cables, bad connections, and defective taps. Our next move involves a project to use fiber optics to replace the coax.

 

[modiconbob]

pc45,
From my experience, most of your problems are still coming from the poor connections, cables and taps. If you utilize the spec'ed QUAD SHIELD cable, you should have negligable interference from the 480v. The issue in using fiber modems with the Modicon product is that you must still utilize a metallic tap and coax to the remote interface (J890 etc.). There are no interfaces that connect directly to fiber.
In the dozens of applications that have I utilized fiber, it has been to increase signal levels due to excessive cable lengths. Of course as you suggest it does eliminate any noise issues which do occur. I would just hate for you to install a bunch of expensive fiber stuff only to have the same problems. What I suggest is that you have the system teated or certified to determine when you stand currently.

 

[ewbdale]

This connector issue will be an issue later on, I had the same problems on a couple of sites and I had my communication cable done by Modicon to and still had comminication drops. I eventually had to scrap the modicon and replaced with another manufacturer.

raspinc.com

 

[modiconbob]

smartscrnexpert,
I feel your pain!
I know the service folks and their knowledge level currently left at Modicon. Unfortunately what you received was less than satisfactory service.
That's why I left the company over 10 years ago. My company now does all of this, design, certify and/or troubleshoot these networks.
Modicon's Remote I/O is bullit proof when installed properly with the correct componants. However it wasn't ever very clear what those specific componant were in their documentation or from the tech support people.

Bob

http://www.deltaautomation.com