Running a PID loop on an FR-D700 inverter

[Div_by_zero]

Hello,

Currently running an FR-D700 inverter by feeding it a 4-20 mA speed reference and pulling the STF run forward signal low.  The VFD is running a ring compressor / regenerative blower.

Would like to change the setup so that a pressure transducer on the low pressure side of the blower feeds the VFD a 4-20 mA signal, and the VFD's on board PID loop modulated the drive speed so that a certain pressure set-point is maintained.

I'm assuming this is possible and a pretty standard setup?  Do I just change some parameters so that it will consider the 4-20 mA loop the PV?  How do I change the SP on the fly?  Is that done via a parameter change, or can a second analog loop be used as the SP?

Thanks for any help!

[kraykov]

Hello colleague,
 

SP for PID can be set from the control panel or external analog input. With a value of the control panel is used Pr.133. We tune Pr. 79 - 3.

Also be used and parameters Pr.128 - Pr.134 and Pr.575, Pr.576.

Start of PID can use terminal RH set to 14 (Pr.182) or automatic switchover frequency Pr.127.

Good luck.

 

Edited January 31, 2016 by kraykov

[Div_by_zero]

Thanks kray, good info.

So what units will Pr.133 be entered in?  Will it be raw A/D counts, 4.000 - 20.000 ma, or something else?

edit: OK, I see it's going to be 0-100 %.

So if the 4-20 mA signal from my pressure transducer is 0-15 PSI, then setting Pr.133 to 50.0 will make the PID's SP=7.5 PSI.  Got it.

Thanks again.

 

 

Edited February 1, 2016 by Div_by_zero

[PiD-PLC]

Hi, can I know step by step how to setup pid controller in inverter D700 ? now my plant running by using PLC Mitsubishi .. thank you :)