Delta Contact for a Range

[BobO]

The only requirement is that the C bits need to be contiguous and aligned on 32 bit boundaries.

[BobO]

And your existing code could be reduced to something much simpler, like what I've attached. The problem is that won't re-trigger properly unless all alarms go completely away. The MATH box approach will trigger a new alarm regardless of the state of previous ones.

[ATU]

Would CHECKSUM run faster than a series of OR'd  Delta Contacts using 32bit registers?  Is CHECKSUM native or one of those encapsulated instructions packed with hidden sub instructions?

[BobO]

Would CHECKSUM run faster than a series of OR'd  Delta Contacts using 32bit registers?  Is CHECKSUM native or one of those encapsulated instructions packed with hidden sub instructions?

It?s native, but it isn?t going to be faster than deltas.

[PLCwannabe]

I assumed that you want a one shot any time a C bit goes from 0 to 1. This single rung triggers on 64 C bits.

Could you explain how this rung works? Is the copy instruction also part of checking all the c's?Thanks.

[BobO]

Could you explain how this rung works? Is the copy instruction also part of checking all the c's?Thanks.

The MATH box is is simply doing a bitwise comparison of the 64 C bits and 64 bits within two D locations. Basically it returns true if any single C bit is set, but the corresponding bit in the Ds is not. Then the COPY just pushes the current state of the Cs into the Ds. It's just detecting the rising edge of the Cs. This allows the alarm handler to trigger in response to each rising edge event.

If you want the alarm handler to run when the first alarm is triggered, and then not run again until all alarms are cleared, then the other rung I gave you will work.