Discrete Input Interrupt for RS5000?

[tommohar 0]

I'm converting a program from RS500 to RS5000 but am getting stuck on what I need to use in place of the DII instruction on RS500. Any suggestions? The 500 subroutine consists of 4 rungs:1st is the IIM,2nd is a rung that enables/disables a solenoid at a high rate of speed, 3rd is the IOM, and 4th is the return. Thanks!

[OkiePC 14]

I have little experience with CLX, but I think you can configure your input card to trigger an interrupt. Another thing with controllogix, you can set your task scan rates independently, so that the scan time and repeatability is very predictable and fast if necessary. The speed with which your I/O are normally updated is configurable also. I believe that when an output bit is changed by the program, the output card gets a Change Of State update, (similar to your IOM instruction in the SLC). The IIM may be unnecessary also since the input cards send an update to the processor on COS (change of state) also. I'm pretty sure it can be done, but you'll have to let one of the experts fill you in on how to actually configure an interrupt in RSLogix5k. I haven't used it in three years and don't have a copy to play with.

[TConnolly 13]

OKiePC is correct. Configure an event task. This task will interrupt any other task whenever the specified IO event happens. Check the online manual under help in Logix5K - common procedures, chapter 4 for information on event tasks as there are multiple ways to trigger an event task. Each event task can be triggered by only one IO point, but you can have multiple event tasks. Also, the IO scan on the CLX is asynchronous with the plc scan because the CLX backplane is a producer/consumer control-net backplane. You need to configure you module update times accordingly and read up on it in the help manuals. There is a technote on buffering IO if you find it absolutely necessary, but most apps don't require it. Edited 31 May 2005 by Alaric

[tommohar 0]

Thanks for the info. I'll try the event task and see how it works and let you know what happens.

[tommohar 0]

So far so good. The only problem I ran into(aside from the archaic mechanical design of the machine) was figuring out how to avoid overlap but after some reading and trial and error programming, I was able to trigger the event properly. Thanks again.