monitor and alarm

[redwood1957]

I have several stations with AB Micro 1200's. At this time they get inputs for two pumps starts and then acumulate run time for each motor.This is then sent via radio modem to a master for alarming.I would like to do the following monitor that the motors are alternating starts, run time is within x amount of each other and alarm if there is two starts with out the other. and monitor run times to see if one pump (motor take excessive run time to satisfy the level set points.
Any suggestions on this.

 

[Lancie1]

Redwood,

The answers to your questions depend on what and how the pumps are now being controlled. To add the functions you mentioned, it is necessary to first get a copy or printout of the program. The answers to your questions depend on what and how the pumps are now being controlled. It seems like you already have a program (same on each PLC?) running on your Allen-Bradley Micrologix 1200 PLCs that causes the pumps to alternate.

To add an alarm based on the number of pump starts, the easiest is probably to add a rung with a Counter that keeps up with how many starts each pump has made.

 

[redwood1957]

Relay logic

I'm sorry these pumps are controlled by relay logic circuits. The PLC monitors only. starts run time and some other things high level,main power. I just want to do a little more than starts and stops. I could use a few of the outputs since we don't use any at this time
Thanks

 

[Lancie1]

Okay, so the control logic is external to the PLC, but you have inputs to the PLC for Pump Started and already have PLC memory storage for accumulated pump run time. It should be easy to add logic to keep up with how many times each pump has started.

At some time, you have to reset and start over. How long is the pump run time accumulated?