SherlockNeo

L18er embedded i/o not responding

7 posts in this topic

Hello, i need your help, i have a problem with my compactlogix 1796-l18er-bb1b plc with module 1734-ib8 24v dc sink in, 1734-vtm, and 1734-ctm.

So first, We are doing some testing, so we need to turn off our machine, but when we turn on it again, the plc is not working properly. The ok, link, and run indicator is solid green, but the i/o led indicator is off, and all of digital input or output indicator is off too. Even when we give 24 v to the input, is not responding. So, we check the output voltage it's only 8.66 volt. Then we checked with software studio5000 there's is a problem with embedded i/o module and the ib8 module, the fault say "connection timed out". And because of that we can't reset the module.

So, my question is there a problem with the plc electric circuit that's make the embedded i/o not working or there's some safety features that I don't know thats make the embedded i/o not responding. And why the output voltage is 8.66 volt. I really appreciate all your help and thankful for every answer.

I also attached some photos of the studio5000 and rslinx 

IMG-20210719-WA0003.jpg

IMG-20210719-WA0000.jpg

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I have not worked with this specific PLC, but have worked with the 1734 Point IO family before.  

1. Make sure that in your testing you did not disturb the module to module backplane.  Make sure they're tightly together left to right.

2. Make sure you have the Terminal Connectors on the face properly seated.  These can look seated and not be so double check this.

If it's not those two things someone who has actually used the PLC may have other suggestions.

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The screen shot shows the L18 is configured for 10 slots.  But there are only three devices. Fix the chassis configuration.

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Great catch @pturmel - i totally missed the config issue.

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Is this a working system or new.?

ive had an L16 embedded IO go bad before, fortunately not much was used so could easily move to the expansion modules. 

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On 7/19/2021 at 4:05 PM, pturmel said:

The screen shot shows the L18 is configured for 10 slots.  But there are only three devices. Fix the chassis configuration.

The 10 slots showing in the RSLinx screen shot is normal and shows the total number of slots available (0-Controller, 1-Embedded I/O, 2 thru 9-Expansion I/O). There is only one expansion module (IB8), as shown. The 1734-VTM and 1734-CTM are Voltage Terminal and Common Terminal Modules that add extra points for wiring field devices. They don't count as I/O modules.

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Every time I've worked with PointIO parts, with both adapters and processors, I've had to adjust the slot count to exactly match the devices installed. 

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