RSLogix 5000 Totalizer Question

I'm adding in some additional totalizer code using an existing template. The person who did the existing code used a gain of .0167 and a time base of zero (seconds) to convert gal/min to gal. It's also in the continuous task. While this seems to produce an accurate total, shouldn't this function only be executed in a periodic task once per second since the time base is in seconds?

What you say makes sense, the instantaneous flow x the gain incremented on the second would give you a totalised value... When you say template, are you talking about an addon instruction ?? If so maybe the time base is internal ??

Lemming said:

What you say makes sense, the instantaneous flow x the gain incremented on the second would give you a totalised value... When you say template, are you talking about an addon instruction ?? If so maybe the time base is internal ??

Click to expand...

By template I just mean how a previous person wrote the code. I'm just wondering if the totalizer function needs to be in a 1 sec periodic task or should stay in the continuous task.

Yes ideally you want functions like totalization in a periodic task. The time base can vary, you just need to convert your flowrates accordingly. If a flowmeter analog input converts to gal/min, you aren't constrained to 1 minute periodic tasks. Convert it to seconds, millisecond...etc. The time base may influence your accuracy so you need to be fast enough to be accurate but slow enough to not add unnecessary overhead to your processor. If you set your periodic task to 10ms, but your analog input only updates data every 100 ms your periodic task might be executing more times than it really needs too.

Is a bit confusing that the code works in the continuous task thou ? Must be a 1 second interval somewhere, or its not working as you suspect. The other way of totalising is to accumulate a fixed volume and vary the timer base on the instantaneous.

Have you seen the ladder running ??

Lemming said:

Is a bit confusing that the code works in the continuous task thou ? Must be a 1 second interval somewhere, or its not working as you suspect. The other way of totalising is to accumulate a fixed volume and vary the timer base on the instantaneous.

Have you seen the ladder running ??

Click to expand...

I've watched it running and it seems to be accurate in the continuous task. It sounds like the totalizer function will work correctly as long as my time base is set correctly. In this case, I'm using gal/min input into the totalizer configured with time base in seconds then set the gain to 1/60 to convert to gal.