SLC500 - Rack error

PLC_SLC500 · Jun 24, 2021

Good Afternoon, First time poster, many week reader.

I am a hobbiest and have an SLC500 system working with RSLogix 500

I at the moment have a 7 slot chassis an IB16 and an OW16 module connected to a 5/04 CPU

the RSLogix software can see all modules correctly however anytime i try and add an output to the ladder logic and run it i get a Data Rack error

I have tried: -
the output module in other slots - same error.
the input module in the same slots as the output was removed from - works reading the input fine.

I have earthed the chassis.

have any of you seen this issue before?

thankyou

plvlce · Jun 24, 2021

PLC_SLC500 said:
Good Afternoon, First time poster, many week reader.

I am a hobbiest and have an SLC500 system working with RSLogix 500

I at the moment have a 7 slot chassis an IB16 and an OW16 module connected to a 5/04 CPU

the RSLogix software can see all modules correctly however anytime i try and add an output to the ladder logic and run it i get a Data Rack error

I have tried: -
the output module in other slots - same error.
the input module in the same slots as the output was removed from - works reading the input fine.

I have earthed the chassis.

have any of you seen this issue before?

thankyou

See a couple threads.

Noise on backlane is a likely cause. Grounding is a good first step; make sure you also have suppression on whatever loads your OW16 is driving.

PLC_SLC500 · Jun 24, 2021

At this point the SLC is: -

SLC500 Chassis with PSU currently fed from 13amp uk plug.
1 input module (working fine)
1 output module (cannot make work)

no loads connected

input 24v taken from PSU connecting ground and input 0 straight to the 24v feed

no output loads connected just a straight module

2.5mm earth cable connecting Chassis (with sanded off paint) to the chassis ground pin on psu which also goes to 13amp plug earth.

i cannot make the SLC any simpler in terms of stripping it down.

PLC_SLC500 · Jun 25, 2021

Curious if anyone has any thoughts.

Engineerj22 · Jun 25, 2021

What output are you trying to turn on? Is the chassis configuration right in the program?

PLC_SLC500 · Jun 25, 2021

any output of the 1746-ow16 interface

i have no load on any of the inputs just trying to test a simple in -> out confirm

Chassis is a 7 slot chassis which is correct.

iv ordered an ob16 just incase its that module which is fubar

OkiePC · Jun 25, 2021

PLC_SLC500 said:
iv ordered an ob16 just incase its that module which is fubar

A rack error or 'stuck runtime' fault is usually caused by a faulty card although if the relays near the backplane were driving a relatively large inductive load, I have seen that cause problems too.

You have no load on the relay outputs, so I concur with your decision. The OB16 should last forever if you only drive small interposing relays with it. Good choice!

Ron Beaufort · Jun 25, 2021

welcome to the forum ...

just to make sure that we're fully understanding you - when you say that the system "sees" the module, you mean that you've set it up in the IO Configuration feature - and then DOWNLOADED the program file into the processor ... is that correct?

my suggestion would be that you save an UPLOADED copy of the present program file (RSS extension) and then post that as an attachment to this forum thread ... (you'll have to ZIP the file before attaching - that's a forum rule) ... maybe we can pick up on some little detail that you've overlooked ...

note that if you use a dropbox (etc.) some of the forum members won't open the file - for security reasons ...

good luck with your project ...
.

James Mcquade · Jun 26, 2021

post your program, zip it first.
maybe there is something you are doing that is causing the issue.
james

I_Automation · Jun 27, 2021

I had a SLC that occasionally faulted showing a problem card in an open slot of a 7 slot rack. 5/03 & 3 IO cards, 3 open slots.

After getting called a few times (the customer didn't want to replace the rack as they didn't have one) I put in 3 IO cards they had on the shelf & set the IO tree in RSLogix with a new download.

Hasn't faulted since, but it should have the rack replaced.

PLC_SLC500 · Jun 27, 2021

First set of pics

PLC_SLC500 · Jun 27, 2021

last pic

This happens whenever the input check becomes true

Ron Beaufort · Jun 27, 2021

short on time - but ...

one of your pictures shows an "extra" module in the chassis/rack ... something like an "adapter" ...

remove that from the rack and try again ... if that cures the issue - then we'll talk about how to properly install that "extra" module ...

and just for completeness - make sure that ONLY the two modules that you're showing on the IO Configuration table are currently installed ...

in simple terms - TAKE THEM OUT OF THE CHASSIS/RACK ... once you get your system working with just the one input module and the one output module - then we can go deeper to physically install any other modules that you want to use ...

gotta go ... good luck with it ...

Ron Beaufort · Jun 27, 2021

BIG IDEA:

among all of the various Allen-Bradley platforms, the SLC platform is absolutely the "pickiest" of having its IO Configuration table PERFECTLY match the actual modules physically installed in its chassis/rack ...

with other AB platforms you might (that's MIGHT) be able to install an extra module - or even leave out one that SHOULD be installed - and MAYBE you can get away with that ...

BUT ...

with the SLC platform - you're asking for trouble ...

TIP: there is a setting in the Status feature where you can tell the system to "ignore" an extra module - or to assume that a missing one is actually present ... but that's another discussion ...

PLC_SLC500 · Jun 27, 2021

That extra module makes no difference if in or out. its there purely to keep it safe.

said module is an 1747-asb

SLC500 - Rack error

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