PID loops

I am using an Allen Bradley Control Logix processor, and RSLogix5000 Function Block Diagrams to program it.I need to know how to use PID loops.I am new to the subject and greatly appreciate it if anyone can direct me to links about it/ help me solve my problem.

My problem

I have a varible which shud work in a deadband.If it goes below the deadband my status bit shud read a 0.If it goes above my max it shud give me a 1.If it is in between it should retain the previous state's value.

My question
Should I use a PID loop?

"Should I use a PID loop?"

Not on a bet!

PID is used for continuous control of a process variable, and is meant for modulating control. You COULD use the alarm functions of a PID loop for your purpose, but that is like using a the James Bond BMW to run to the store for milk!

You need to use two comparison statements, a setpoint, and a deadband. When the measured value exceeds the setpoint (>), turn on a bit and latch it on. Subtract the deadband from the setpoint, and that is the lower limit. When the measured value is below (<) the lower limit turn of the bit.