Need some Modicon help

[JeffB]

Hi everyone,

I'm programming a quantum 434 using Proworx Nxt. I need to set an internal bit whenever a value stored in a register does not equal zero. I would like to know what instruction to use to do this.

Thanks for any help.

[Tom Jenkins]

The test instruction will do what you want. I'm using Concept 984, but it should be pretty close. Just put your coil on the appropriate ouput.

[TConnolly]

You can also use the SUB instruction and discard the result.



+--------+
| A +-----( ) A >B
| |
| |
| B +-----( ) A=B
| |
| SUB |
| DISCARD+-----( ) A<B
+--------+


Edit,
OK for some reason the [ladder] tag is not working to display this correctly.... maybe this will help.

http://www.plctalk.net/qanda/uploads/SUB.JPG

[Jim Dungar]

Actually it is even easier with your Quantum and 984LL. Simply use the NBIT (bit assumes state of input contact),NCBT (checks if bit is closed), NOBT (checks if bit is open), SBIT (set bit on), and RBIT (reset bit off) commands to directly access any bit of any 4x word.