grnick50
Lifetime Supporting Member
Hello,
I have already searched for that in the forum but did not get any satisfying answer, so here it goes:
I have a 1769-L36ERM that controls an Auma regulating valve. The valve expexts from the PLC two outputs, one for close and one for open. It also provides to the PLC a 4-20mA signal of the position of the valve. The use of the valve is to reduce the temperature of a hot water line, by injecting cooler water into it.
I intend to program a PID loop where my PV will be the temp of the water line and the SP will come from a SCADA.
From past experience I know that The PID block in Logix5000 provides its output in percent as an analog value. The question is how can this be converted to two discrete signals for closing and opening the valve. I have read that it be programmed as a time proportional conversion.
What I am looking for is to avoid programming that myself. I would prefer a well proven built in instruction that does that like it happens with Siemens.
Another question is what to do with the position feedback I get from the valve, apart from using it for monitoring and trending purposes.
Regards
I have already searched for that in the forum but did not get any satisfying answer, so here it goes:
I have a 1769-L36ERM that controls an Auma regulating valve. The valve expexts from the PLC two outputs, one for close and one for open. It also provides to the PLC a 4-20mA signal of the position of the valve. The use of the valve is to reduce the temperature of a hot water line, by injecting cooler water into it.
I intend to program a PID loop where my PV will be the temp of the water line and the SP will come from a SCADA.
From past experience I know that The PID block in Logix5000 provides its output in percent as an analog value. The question is how can this be converted to two discrete signals for closing and opening the valve. I have read that it be programmed as a time proportional conversion.
What I am looking for is to avoid programming that myself. I would prefer a well proven built in instruction that does that like it happens with Siemens.
Another question is what to do with the position feedback I get from the valve, apart from using it for monitoring and trending purposes.
Regards