Long totalizing timer function needed

[DaProgrammer 0]

Using CX-One I need a function to track total time that a specific output is turned on. When the output is off I need the timer to stop but retain its value and reset only on demand. This is a filter change function for an intermittent pump that will need send a flag after say 40 hours of actual pump on-time to instruct the user to change the filter. The standard timers zero out when the execution condition turns off and the TTIM counter maxes out at 999.9 seconds. Can anyone help with this? Edited 18 Nov 2009 by DaProgrammer

[d2b 0]

DA Have you considered using a (1 minute) timer in conjunction with a CNTR (reversible counter) to accumulate your time? I think it will work. I have done something similar with AB. Everytime the timer times out you can use a one-shot (UP) to increment the counter and a work bit to reset the timer. Does this make sense? D2B

[lostcontrol 23]

Or just increment a register, and only reset the register when required...

[DaProgrammer 0]

Thanks, the 1 minute TIM>>CNTR approach should work just fine.

[pfort 20]

I think that lostcontrol idea was better because in case of power lost, timer and counter are reseted. All you need is a 1 min pulse flag and an increment instruction. Comparison and reset to zero when value reached.

[DaProgrammer 0]

Thats actually slightly simlpler but as a rookie programmer I want to clarify this - an Increment instruction retains its value even in the event of a power loss?

[BITS N BYTES 66]

As long as you Increment D memory, the value will be retentive.

[lostcontrol 23]

Or H memory...

[Jay Anthony 118]

CNT and CNTR are data retentive.

[pfort 20]

OOOooooopsss

[BobB 58]

With the function @INC or @++ or @++L (depending on the PLC) you can increment either a DM (retentive) or CIO channel (non-retentive) as you wish - ++L is long. To reset just MOV #0000 or MOVL #00000000 into the counting channel. Use @ or the channel will increment while ever the closk pulse is on giving you 'unexpected' results.

[Mr_Ritz 0]

I regularly use the totalising timer funtion for pump minute counters along with a long word increment, incrementing 2 DM words. The only problem with your 1 minute counters is that the output could run 50 seconds then go off, start again and start counting the timer from the start again, hence losing best part of a minute. Over enough cycles the filter could run miles out of spec. Use BSET function to reset once the filter has been changed.