Minimum/Maximum Question

[Debnil]

Hello everyone, I have a problem that I haven't been able to come up with a solution to. I'm running Lookout 5.1 interfaced to a GE Fanuc 90/30 PLC. I have a thermocouple input that I want to monitor. I want to setup an alarm that will be tripped if the temperature changed +- 2 degrees over a 24 hour period (running constantly 24/7). I thought of using the minimum/maximum objects but noticed it only tells you the min or max for the past 35 data points. Anyone have any suggestions at to how I can create this alarm? Thanks!!

[Ryan.S]

I'm afraid you misunderstand the meaning of 35.

This object continuously calculates the max value for all the data from the last time you reset it.  Everytime you reset it, the current max value will be stored to "maximum.1". It can store the last 35 max values.  

You can test it by yourself. Connect a "waveform.random" to it and a pushbutton to "reset".

So, I mean you can accomplish what you want by min/max objects.  Regarding the 24h period, you just need to reset it everyday.

[Debnil]

Thanks Ryan,

Only problem is that it needs to be rolling without the operator reseting the value every 24 hours.  Any idea how I could accomplish this?  Thanks! - Debnil

[Ryan.S]

TimeofDay object can help you. It's period is 1 day. It goes TRUE for once everyday and keeps TRUE for the duration you set.

You can use TimeofMinute to test. It has the similar function but the period is 1 min.