Hello all and thanks in advance for the help.
I have been asked to use an existing drive with a new control system. At the moment I have it fully setup other than the speed reference.
Old setup:
This drive internally produces a 0 to -10 volt signal which was then ran to a 500Ohm Pot(-10 to top, a special +.2V to bottom, and a shield connected to common, and the reference signal), and the returned signal was the speed reference, 0 being 0% and -10V being 100%.
Verification:
I have looped the -10V directly into the input for the reference signal on the drive and everything powered up and moved correctly.
Attempt 1:
I have a MicroLogix PLC with a 1769-OF2 Analog output module, which is configured to output -10 to 10, and scaled in the ladder to output 0 to -10 just as the drive was setup to receive. I connected the common from the output card to the common of the drive, and the output V+ from the card to the speed reference input on the drive. This did not work.
Thoughts:
Find a device that will accept the 0 to -10 from the drive and adjust an output signal from that source, based on an input from my PLC. I am not sure what sort of signal conditioning or isolation terminology such a device may be called, does anyone have some thoughts? Please list links to possible device information, if possible.
Thanks,
Jamie
I have been asked to use an existing drive with a new control system. At the moment I have it fully setup other than the speed reference.
Old setup:
This drive internally produces a 0 to -10 volt signal which was then ran to a 500Ohm Pot(-10 to top, a special +.2V to bottom, and a shield connected to common, and the reference signal), and the returned signal was the speed reference, 0 being 0% and -10V being 100%.
Verification:
I have looped the -10V directly into the input for the reference signal on the drive and everything powered up and moved correctly.
Attempt 1:
I have a MicroLogix PLC with a 1769-OF2 Analog output module, which is configured to output -10 to 10, and scaled in the ladder to output 0 to -10 just as the drive was setup to receive. I connected the common from the output card to the common of the drive, and the output V+ from the card to the speed reference input on the drive. This did not work.
Thoughts:
Find a device that will accept the 0 to -10 from the drive and adjust an output signal from that source, based on an input from my PLC. I am not sure what sort of signal conditioning or isolation terminology such a device may be called, does anyone have some thoughts? Please list links to possible device information, if possible.
Thanks,
Jamie