ControlLogix FLL for Boolean

Hi

Not sure of 1 instruction but I would normally use dints and not bools.
If I was to do this I would use indirect addressing and then you could set to 1 or set all to 0 in one line of code.

I am not at my pc at the moment but if you need an example just reply I could post it


Donnchadh

You can't use FLL for BOOL. However, you can create a UDT with a BOOL array and then use the instruction.

I don't think you would necessarily need a UDT for this. Just create a BOOL array equal in length to the BOOL array you are currently using, call it BOOL_Null.
If you are using v20 Logix5k software and firmware, then make the Null array a constant. This will insure the array stays filled with 0's.
Then if you want to "clear" the bits 500-599 of the existing array, then just COP BOOL_Null[0] BOOL[500] 100.
Disclaimer: I haven't tried this in Logix5k, so I'm not 100% about using the COP instruction on a BOOL array, but I don't see why it shouldn't work.

One possible way might be to use a FOR instruction to call a routine a number of times depending on the number of boolean bits you want to write 1 to.

In the routine use an unconditional OTE to write 1 to the tags with the help of indirect addressing i.e,the OTE address should look like:

Tag

I should be the DINT type tag which you have used in the "Index" operand of the FOR instruction.

Similarly you can use a FOR to call a routine to write zeroes.Execute only one FOR instruction at a time to avoid both of them writing opposite values to the same address.

Hi Anirban Hazra,

I'm new in PLC world and I'd like to know how can I make a FOR instruction on RsLogix 500?
I'm using a Micrologix 1400