Simple Question for an IO checkout

Hello all hope all is well,

Their is a big project that I'm currently modifying the plc program to. Before i fully implement for a Start up i always like to do an IO checkout first.

So here is my question:

The PLC is a SLC 5/05

if i disable the routines the call the IO with an always off or an AFI instruction, then proceed to Force the Outputs for testing to see if they work and for the inputs if i just see the input data tables will that work for an IO checkout, all the IO is digital btw. So let me know as i have not used SLC plc's before. Thanks in advance.

If you don't execute the routines that actually contain output instructions for the digital outputs, the controller won't put any values into that data table.

In such a case, you won't even need to use the "Force" feature. You'll just open the Data Table monitor and put a "1" into the field you want to turn on. It will remain true until you put a "0" into it.

As long as you are in RUN mode, the values in the Output Data Table will be physically commanded on the Output Modules. Switch to PROG mode, and all the outputs turn off.

Thanks for the reply. I would also assume that the input image data table will update if an actual input out there in the real world switches right?

Yes, the input data table updates constantly no matter what mode the SLC-500 controller is in.

The Output data table is only written to the physical output modules when the controller is in RUN or Remote RUN modes.

although thats pretty obvious just wanted to be sure, Thanks.

Not a problem.

Notable exceptions from the A-B world; analog modules in PLC-5 systems or networked modules in SLC systems that require block transfer logic or a Scanner "Run" bit like on DeviceNet, or modules whose slots have been inhibited.

But for ordinary in-chassis SLC-500 I/O, they work just like you expect.

hmmmm that brings me to another question related to this, their is the SLC 5/05 CPU, on its rack the last slot is a 1747-SN module for expansion of remote IO, that has a 3 wire, blue hose connector that goes to two different remote IO modules (1747-ASB) that have their own set of IO on their corresponding racks. The beginning and the end have terminating resistors. We are completely taking out one of the remote racks. and keeping one as is. Now in your IO configuration in your PLC, all i see is the 1747-SN module in the last slot i don't see anywhere the 1747-ASB modules. And in you IO data tables your remote data looks just like regular IO.

So my question is if we are taking out one of the 1747-ASB modules, and assuming we correctly wire up the terminating resistors etc, will that take care of it or is their something i'm missing here?

You will want to examine the DIP switch settings on the 1747-ASB modules and figure out which "Rack" number they are using, which determines where they'll be in the I/O table for the 1747-SN.

You'll also want to reconfigure the 1747-SN's scanlist. This is done with the "Edit G Data" button in the 1747-SN's Advanced Configuration.

It can be tricky for novices, because it uses late 1970's era terminology for "Racks" and "Quarters". Make a list of all of the I/O modules, and note all the DIP switch settings, and folks can help you through it.

The RIO network will still function with an un-edited Scanlist (aka G-file), but you will have a nuisance fault on the scanner and the network will run a little slower because it's timing out waiting for data from the absent adapter.

I don't remember if the Input data for the 1747-SN updates while the controller is in Program Mode. You'll have to experiment.

Great thanks on the info. I should be able to get that info tomorrow, and it looks like in the G gile config settings their is a check box for Logical rack 0 which is checked and logical rack 1 which is also check i have a feeling one of these will be unchecked once i verify which one and hopefully that should be it.

How can you truly do an I/O checkout without actually energizing the outputs and actuating the the device using the field wiring?

Same for the inputs, where you actuate the limit switch and see the bit toggle in the data table.

anything less is not an I/O checkout.

You may need to remove the output fuses or disable the outputs when checking the inputs.

@dogleg43, i may have failed to mention that but of course that's what you would have to do, by actuating solenoids, or using some kind of reflectors for photo eyes in my case.