rslogix5000 question. maybe dumb.

can I use a mov instruction to move a 0 into a boolean data type? I dont have a way to test it right now and I never tried this.

Just use an OTU

diat150 said:

can I use a mov instruction to move a 0 into a boolean data type? I dont have a way to test it right now and I never tried this.

Click to expand...

It won't work. The Rslogix compilier that you are moving a DINT into a BOOL and give a parameter type mismatch error

MOV doesn't support BOOL operations. It supports:

SINT
INT
DINT
REAL

ok here is the scenario. I am looking at some data from a different device via wonderware. wonderware is setup to toggle a boolean data type register "on" in the plc when I have a alarm state on that device. the policy is that wonderware will only toggle the bit high, not toggle it back to zero. I need to figure out a way to toggle that bit back to zero after the plc scans that routine which would register my first out alarm.

I know that I can do this if i have wonderware write a integer to a register and then do a greater than which would then set the bit. then I can move a zero back into that register at the end of the scan. I may end up having to do that depending on what the wonderware guy does.

do I have any options to toggle that boolean bit back to zero another way, without using a integer?

Yes, the instruction is OTU. That's all you need.

CroCop said:

Yes, the instruction is OTU. That's all you need.

Click to expand...

ok would it be setup like this


---[bit]------------------(bit)latch



---[bit]-------------------(bit)unlatch


where all of the bits are the same?

or would I just need to do this at the end of my routine and not worry about the latch?


----[bit]------------(bit)unlatch

excuse my ignorance on this. we never use latch or unlatch in our programs.

Without seeing your application, I can not comment on the logic nessecary for correct operation.
The OTU instruction will write a 0 to the bit level. Read in the help file if that isn't clear enough.

It's perfectly fine to have just the unlatch.

thanks for the help.