AB rslogix 5000 instruction logic...

AmazingTrans · Sep 12, 2011

Hi there,

I have a word with 16 bits. I want to do a logic where it check if any two bits are true, trigger an output. What type of instruction should i use?

Hope someone have a solution.

Thanks!

TheWaterboy · Sep 12, 2011

test for a value greater than ONE?

jkerekes · Sep 12, 2011

Does it have to be exactly two or is it two or more? How about taking the word value modulus 2? If the result is 1, then two or more bits are true.

bernie_carlton · Sep 12, 2011

TheWaterboy - this checks for two or more bits. And it may fail if the math treats the location as signed and the MSB is '1'.

jkerekes - mod 2 = 1 just shows odd. The original may be '1'.

I you need exactly 2 bits then try this algorithm. If it needs two executions to clear the number then you have it.

jkerekes · Sep 12, 2011

Oops. My mistake. Too quick in posting.

AmazingTrans · Sep 12, 2011

Thanks for everybody quick reply.
Yes, i am only looking for 2 bits and it can be in any position of the 16 bits. As long 2 bits are high, trigger the output.

jkerekes · Sep 12, 2011

OK. Let's try this again.

How about the FBC function? This will find all the mismatches. If the result .LEN = 2, then you can act on it. If it isn't, ignore.

widelto · Sep 12, 2011

I will use bit shift register whenever more than two bits at the output are 1 then trigger an output.

jcp · Sep 12, 2011

Hi
FBC function is best.
regards

AmazingTrans · Sep 12, 2011

Thanks again for everybody reply.
I'll try FBC.

AB rslogix 5000 instruction logic...

AmazingTrans

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