1794 Flex IO modules not showing up

I'm trying to communicate with some Flex IO modules from a ControlLogix PLC but I'm not having much luck.

1756-L61 -> 1756-ENBT/A -> 1794-AENT
Connected to the AENT are the following
0. 1794-OB16/A
1. 1794-OB16/A
2. 1794-OB16/A
3. 1794-OB16/A
4. 1794-IE8/B
5. 1794-OE4/B
6. 1794-IB8/A

I can access the 1794-AENT fine, it shows up in RsLinx and in the RsLogix 5000 project. All of the modules have a yellow exclamation mark in RsLogix though (Code 16#0203 connection timed out) and don't show under the 1794-AENT in RsLogix.

The weird thing is when I was poking around the Flex IO last night two of the modules showed up in RsLinx (the two analogue modules in positions 4 & 5) and the error code for those two modules in RsLogix changed to something along the lines of "configuration format rejected".

Any ideas?

The Flex IO is mounted in a panel at the moment so the next step might be to pull them out and put them on the bench to test them.

RsLogix:


RsLinx:

I notice that your local I/O also have warning icons associated with them. Could it be that you need to put the PAC in run mode to establish connections to all these modules? This is just a guess, I am still a novice with Compactlogix.

Also, (another guess), since your RSLinx view of the modules does not show a "+" next to "Proxied Modular..." then perhaps RSLinx is missing one or more eds file(s) for either the adapter or the modules?

I would check all of the wiring bases to be sure they are properly plugged into the adjacent base. Also look for bent pins. It appears that the Flex adapter is not communicating to the modules on the Flexbus.

There is something iffy with the network's topology...
The RSLinx RSWho is browsing a subnet containing both the 1756-ENBT and the 1794-AENT adapter, presumably the one included within the RSL5K project together with two other CPUs.
First of all, according to the RSL5K application file, the Flex chassis contains 7 (seven) modules; RSLinx states that the chassis is an 8 (eight) slot one. You should edit the RSL5K module's configuration and mitigate the discrepancy; if there are 7 installed modules then the chassis size is 7.
Secondly, the 1794-AENT should be patched within a dedicated 1756-ENBT bridge's Level 0 subnet; the RSWho indicates that the AENT is patched within a level 1 subnet, containing 2 SLC 5/05s.
Personally, I have never encountered a functional topology laid out this way; the common procedure is to segregate Level 0 I/O communications from any other, peer to peer (Level 1) networks. I would install another 1756-ENBT within the Logix chassis, add it to the RSL5K project and then patch the 1794-AENT subnet to this I/O dedicated bridge; you could still go Online with the L61 using the existing bridge, however the 1794-AENT will be networked within a strictly implicitly communicating subnet.

I have run into a similar problem with a 1794-AENTR turned out that the 1756-ENBT firmware needed to 4.3 or higher again this was in DLR network but might be worth looking into.
Wait never mind your using a L61 apparently my problem only applied to the L7x

OkiePC said:

I notice that your local I/O also have warning icons associated with them. Could it be that you need to put the PAC in run mode to establish connections to all these modules?

Click to expand...

I agree with OkiePC, if you look carefully, all the I/O's are not responding even the ones which are on the local rack (slot 3 & 4). Select I/O configuration and see if it gives you any fault codes/descriptions. As for the Flex I/O, can you ping the IP address of the flex I/O adaptor to check that the adaptor is responding.

I don't have a problem with the 1794-AENT being on the same IP network as everything else; this is fairly common if you have managed switches handling any multicast data.

The "8 slot" text on the FLEXbus is probably the capacity, not the size.

I would focus on why the local 1756 modules have connection failures; are we sure that the 1756-ENBT and those I/O modules are really in the Slot Numbers described in the I/O configuration ?

Also, are the discrete FLEX modules configured as Rack Optimized or as direct Module connections ?

I agree with Paul's suggestion that the lack of a [+] sign next to the 1794-AENT is a concern, but I'm not familiar with any EDS for the 1794 Flexbus, like you need with a Bulletin 1769 Compact backplane. Maybe the 1794-AENT EDS file itself is not properly installed.

OK so the electrician had bent a heap on pins between the bases..

I can now see all the modules except the 2 analogue modules. I'm suspecting the socket on the 1794-CE3 cable joining the top and bottom rows (from module 3 to 4) is damaged.

Thanks heaps for all of the quick suggestions.

I just connected the cable directly from the AENT to a single terminal base with the analogue module in it and it shows up! Now I am getting really confused.

Do the analogue modules have to be in the first 4 positions or something?

One bent pin may lead to enough damage to cause a power drop. I would expect the analog module to be more sensitive to that, but more likely, the module with the bent pin or the socket into which it was plugged is still faulty.

EDIT: Heap of pins?!? Yes, 75% sure you got at least one that's either broke off or a tore up socket.

jazd said:

I just connected the cable directly from the AENT to a single terminal base with the analogue module in it and it shows up! Now I am getting really confused.

Do the analogue modules have to be in the first 4 positions or something?

Click to expand...

That is an issue with any analog Flex since the DeviceNet era...
On DeviceNet PLC/SLC networks I have never gotten lucky with analog modules installed in slots higher than 2; every new install contained the analog modules in slots 0-2; if more were needed we added another DNet node...
Back to Flex EtherNet/IP...
I agree with Ken about the functionality of topologies such as yours with proper managed switching, however, your analog Flex modules are pretty "far" from the comms adapter and since an analog module has a sizeable "data footprint" ( especially Status and Configuration)the network's topology might not permit the CPU to establish connections with the analog modules within the AENT's configured RPI.
We have functional EtherNet/IP Flex racks with analog modules installed in slots 5-6-7, however, they are patched on I/O dedicated 1756 bridges subnets.
You might want to try installing the Flex analog modules within the first three slots of your remote rack and give it another try... That might just do it....

MATT116 said:

I have run into a similar problem with a 1794-AENTR turned out that the 1756-ENBT firmware needed to 4.3 or higher again this was in DLR network but might be worth looking into.
Wait never mind your using a L61 apparently my problem only applied to the L7x

Click to expand...

Yep. Same issue, with somewhat same specs. L63, 1756-ENBT and 1794-AENTR. Upgraded 1756-ENBT firmware from 4.3 to 6.6. Issue resolved.