CompactLogix I/O Not Responding

[micky]

I have a remote rack that has progressively gotten worse in giving me "I/O Not Responding" errors. Started faulting every couple days to today where it faults every 30mins or so. The Ethernet between the PLC and AENTR is straight out of the Ethernet port of the PLC to the AENTR. The 1st and 2nd card are the cards faulting out. These cards have a combination of inductive proxes and limit switches.

So far I have removed every card and verified no bents pins. All connectors between modules are clicked and seated in place. No more than 8 modules are away from the power supply. Eliminated all ethernet switches between PLC and remote rack. I have swapped input modules around and the problem sticks to the 1st and 2nd modules.

Right now the only thing I can think of is swapping out the AENTR.

The remote rack layout is attached.

These are the proxes they are using http://www.automationdirect.com/adc...on/Standard_Sensing_Distance_(18mm)/AK1-A0-2A

 

[Ani]

Hi,

Looks like your modules are OK. It should be fine by moving 1 or 2 modules (specially 1769-IF8/A) to some other racks.

 

[Firejo]

When you say “The Ethernet between the PLC and AENTR is straight out of the Ethernet port of the PLC to the AENTR” are you saying there is nothing but a cat5 cable or is there one or more switches/hubs in the mix? If there are, what else is on them? The 1769 has a limit to the number of connections it can have and it kinda sounds like you might be reaching the limit. If there is other EtherNet/IP equipment on the network the connections in your 1769 might be getting occupied by them even though they aren’t supposed to be talking to your PAC. Would it be possible to connect directly to the AENTR with a cat5 cable (if you’re not already)?

 

[micky]

Nothing in between. The second Ethernet port of the PAC goes straight to the 1st port of the AENTR. The 1st Ethernet port of the PAC goes to a switch which goes to a Micrologix and HMI.

Just checked in on it and now all the IQ16s are faulted out.

 

[PLC GURU]

end cap resistor good? no issues? good connection? Power supply good?

 

[JaxGTO]

I usually slow the update rate that Logix5000 puts in by default to a slower rate. 100ms is fast enough for almost all IO modules.

 

[jvdcande]

... No more than 8 modules are away from the power supply. ...

I remember from the last time I used CompactLogix that the manual clearly stated that the power supply has to be in the middle of the rack as well. Is that the case? If not, you might try to change the PS position.

 

[GTUnit]

Does the firmware version you configured in the RSLogix tree exactly match the firmware version printed on each modules sticker?
Is "compatible keying" checked in the same config?

 

[micky]

end cap resistor good? no issues? good connection? Power supply good?

Other than this a new installation, I assume they are functioning fine.

I usually slow the update rate that Logix5000 puts in by default to a slower rate. 100ms is fast enough for almost all IO modules.

Slowed it down to 250ms and still faults.

I remember from the last time I used CompactLogix that the manual clearly stated that the power supply has to be in the middle of the rack as well. Is that the case? If not, you might try to change the PS position.

Power supply has 7 modules on left and 2 on right. Manual for PS only mentions no more than 8 modules on ether side. Will have to see if I have enough slack to move things around.

Does the firmware version you configured in the RSLogix tree exactly match the firmware version printed on each modules sticker?
Is "compatible keying" checked in the same config?

Firmware matches and all are setup for "compatible keying"

I have a new AENTR on the way and will see if this clears things up.

 

[micky]

Got it worked out. When reading through the manual again when I went to replace the AENTR it noted it had to be within 5 spaces of the power supply.

 

[Geospark]

...had to be within 5 spaces of the power supply.

Oh sorry, I missed this thread!

Yes, yes...

582910 - Compact 1769-AENTR Ethernet/IP Adapter Distance Rating
Access Level: Everyone

You have to remember that the 1769 power supplies provide their rated power to both sides. For instance, a 1769-PB2 power supply can provide 2 Amps @ 5 VDC on the backplane, or 2000mA.

The 1769-AENTR draws 0.5 Amps @ 5 VDC, or 500mA. This module is one of the higher consumers within the 1769 module range. The 1769-AENTR must reside on the left most position of the I/O bank, similar to a controller. If you place too many modules between it and the power supply then it will suffer i.e. its RPI will suffer.

While they state maximum modules per side ratings like 8 modules, these are more for the standard I/O modules. For instance, each 1769-IQ16 input module draws just 115mA @ 5 VDC. Once you start using speciality modules the current draw tends to go up. For instance, a 1769-HSC draws 425mA @ 5 VDC, which is considerably more than the standard I/O modules. This is why speciality modules tend to have a shorter distance rating from the power supply. The 1769-HSC has a 4 module distance rating.

You should always validate the I/O layout for a 1769 chassis, especially when using a lot of modules on one bank and/or a mixture of standard and speciality modules.

Regards,
George