Analoge output controlling loading solenoid valves!
Analoge output controlling loading solenoid valves!
(OP)
hi everybody,
can i use the pid-loop output to control my recip-compressor's loading solenoid valves, for example:
solenoid valve 1 will be energized if pid output > 10 %
solenoid valve 2 will be energized if pid output > 30 %
and so on..
and why?
thankyou alot.
can i use the pid-loop output to control my recip-compressor's loading solenoid valves, for example:
solenoid valve 1 will be energized if pid output > 10 %
solenoid valve 2 will be energized if pid output > 30 %
and so on..
and why?
thankyou alot.





RE: Analoge output controlling loading solenoid valves!
Probably not, at least not directly. You could probably cascade the analog output of the PID controller into an analog input, and use the value to trigger one or more digital outputs.
Why? I don't know why you would want to do that. The value of a PID controller is largely lost if you have only on/off devices to control (unless you have a lot of them)
RE: Analoge output controlling loading solenoid valves!
One possibility would be to convert the analog into a pulse width modulated signal that can control the solenoid.
TTFN
RE: Analoge output controlling loading solenoid valves!
If this is a large machine using such an arrangement, you could do a lot of damage to unloader mechanism, valve discs and plates applying pulse width modulation at anything like normal pulse rates and intervals.
If the motor and the system will tolerate it and you need to use P & ID (though I don't know why you would) consider a VFD. We have applied them through 600 Hp on recips...
RE: Analoge output controlling loading solenoid valves!
I don't know much about loader sol. valves, but I knnow the loop can be used to drive DOs in this fashion- whether it will harm the machine in this scenario, I can't tell you.
Ed
RE: Analoge output controlling loading solenoid valves!
Check out www.kele.com. They have this nifty contoller that will hook up to the output of a process controller. You then use a potentiometer to control when the out put relays come on.
So if your controller has a 0-1VDC output you can set unloader #1 to 5 V and unloader #2 to 10VDC.
RE: Analoge output controlling loading solenoid valves!
Analog is coventionally 0 to 5V, 0 to 10V or 4 to 20Ma or...
Although there are solenoids that are proportional to a variable signal these devices are not usually adapted to the device or machine you want to control, eg, Carlyle Refrigeration compressor unloaders will not respond to a process signal of any kind except on/off at the rated coil voltage.
Thats not to say they will not respond to a time proportioned signal of X% time ON (open)and X% time OFF (closed).
IMHO
Good Luck
pennpoint
Best regards
pennpoint