Any successful PLS modules on ControlLogix


Thread Starter

Trevor Ousey

Hi all,

We have been trying to implement a ControlLogix PLS module unsuccessfully and am curious if there has been much success with the unit. Local GTS support from Rockwell has been disappointing as they have advised us it is not supported in Australia, and none have been sold in Australia. But this was purchased through the distributor.

Anyway, we have used the example program supplied with RSLogix V7.02, and have not had any luck with getting the outputs to operate with positional setpoints. The outputs can be operated via the override bits. We can also view the resolver position.

Any suggestions appreciated.

Trevor Ousey.
Try rev 8.02 or the Beta Version 10 of RSLogix. You can download it from the internet!! There support group is horrible. Who cares if you use the module in Australia, the US or on the planet Mars. They should be able to support it anywhere! This is suppose to be state of the art technology!! Good luck TT
More details are always good, but I'll give you the one question (out of eight I've heard) that was asked three times (does that qualify as a FAQ ?)

The documentation for the 1756-PLS refers to a "RPM Enable" bit, which was never actually added to the functionality of the module. Instead, the RPM Limit Enable is implicit when you load a nonzero value into the RPMEnableHighLimit and RPMEnableLowLimit tags and load the configuration tags into the module.

From the Mars support line,

Ken Roach
A-B Seattle
[email protected]

Jarrod Marks


Thanks for the reply re. the 1756-PLS module, but unfortunately, the "RPM Enable" bit isn't the problem. We're using a Logix 5555 processor,
RSLogix 5000 version V8.02.00, RSLinx Lite version 2.30.01 (Build 48), and version 2.2 of the "Messaging_Configuration_1756_PLS.ACD" sample
program. For the moment, I simply want to get the sample program working, so that I can see first hand the details in the module's
operation. Also, the firmware is of the correct version for the system we're using.

We have tried recreating the "exact" conditions of the sample program (processor match, etc.) with no luck. We have set the "Enable Outputs" bit and other obvious ones. I thought there might be a problem with the module itself, but using "Output Override" and a multimeter, all the outputs are operational, they just don't work within the program. The resolver connected works, and I can use the "Position" value in a processor program to set outputs on a separate Output module. However, we want the PLS to check limits and set outputs internally, so we get the fastest response possible.

The user manual I've got here (Publication 1756-UM002A-US-P-February 2000, page 5-3) makes reference to either a version 2.5 of the sample
code or version 2.5 of RSLogix5000. If it does refer to an updated version of the sample program, is there any way I can get a copy of this?
Otherwise, have you got any more ideas as to why this module isn't working? It will probably be sent off to AB repairers later this week to
do a more exhaustive test on the module.


Jarrod Marks.