Emerson GE R3Xi - Write to %I bits

[moistcat]

Hi All,
I am trying to write some simulation logic for an existing project im working on.


Does anyone know if this is possible to write to single bits of %I registers? My attached example compiles but does not run as expected.

 

[parky]

Do not know Emerson, however, most platforms do not respond to forcing of inputs (some simulators do allow it), the answer is to map the inputs to internal bits in a program & use the internal bits in the main program, for simulation you remove or disable the call to the input mapping & just enable the simulation program, whewn tested just remove the simyulation code & re-enable the call to the input mapping I do it all the time I usually name the real inputs like Cyl_1_Fwd_PX & Cyl_1_Fwd_PXM for the mapped bit then just use this in the main programs. Example:

Mapping block: (disabled for simulation)
A Cyl_1_Fwd_PX = Cyl_1_Fwd_PXM (map the real input to internal bit)

Main program
A Cyl_1_Fwd_PXM out xxxx.

The simulation Block: (Enabled for simulation)
A xxx. ANxxx. OUT Cyl_1_Fwd_PXM
I do similar for the analogues map them in then disable them for testing.
Sometimes if using a real PLC without the actual I/O I do the same for the outputs so the PLC does not fault as there is no real in/out cards.

 

[Steve Bailey]

The Rx3i permits using input addresses for output instructions. I have done it, but not exactly the same as you've shown. Instead of using a bit of a WORD variable, I always used the absolute address for the -( )- instruction. So I would have used boolean variables %I00177 and %I00178 instead of %I00177.0 and %I00177.1.

 

[moistcat]

Ahhh thats the business Steve. I didnt think to do that.. I got it working by copying input word to temp %R word, executing my logic using BitSet and BitClr blocks, then copying temp reg back to %I..

I just tested your method and can confirm is 100x nicer.
I just didnt think to create boolean tags on the %I registers..
Thanks.

 

[NetNathan]

The Rx3i permits using input addresses for output instructions. I have done it, but not exactly the same as you've shown. Instead of using a bit of a WORD variable, I always used the absolute address for the -( )- instruction. So I would have used boolean variables %I00177 and %I00178 instead of %I00177.0 and %I00177.1.

Boolean read and writing of "I" bits is preferred. I have written a "0" or a "1" to an array of Boolean bits treating them as a word to turn on/off a string of consecutive "I" bits, that are not part of plc IO.
Do not really know why you need to do this with "I" bits. I normally use "M" (memory) bits for this.
To me an "I" bit is an input...you may confuse things in interpretation of the logic treating them as outputs.

 

[Steve Bailey]

Nathan, the OP is trying to create a simulation program block where he can manipulate the inputs in response to turning outputs on or off elsewhere in the program.

 

[NetNathan]

Nathan, the OP is trying to create a simulation program block where he can manipulate the inputs in response to turning outputs on or off elsewhere in the program.

Understood