text: <s>[INST] Powerflex 700 speed control, speed units RPM I have a couple of issues using ControlLogix to control the speed of a PF700 with parameter 79 (Speed Units) set to RPM. The desired speed is set from the PLC logic by assigning a value to the controller tag MyDrive: O.CommandedFreq. One might expect this value to be in RPM, but it isn't. By trial and error I find I need to multiply the desired speed in RPM by 13.654 before storing it in CommandedFreq. This gives a 'Commanded Speed' (parameter 2) in the drive which corresponds with the desired speed in RPM. Where does this scaling factor come from? I'm not getting a linear response from the motor in terms of the actual speed achieved. If I set CommandedFreq to 5000 then I get a Commanded Speed (P2) of 366.2RPM and a Speed Feedback (P25) of 366.2RPM - perfect. But a CommandedFreq of 10000 yields a Commanded Speed of 732.4 (perfect) but a Speed Feedback of 754.8. P23 Speed Reference always matches the Commanded Speed, but the motor is actually turning at the speed indicated by Speed Feedback. So the faster I ask it to go the more it overspeeds. Are there some drive parameters which need tweaking to address this? If anyone can point me at some relevant doc for this stuff that would be a great help. None of the manuals make any reference to the .CommandedFreq units being anything other than Hz (or implicitly RPM if Speed Units is RPM). Mike [/INST] Helpful chap at Rockwell TechConnect may have solved this for me - doing some calcs & checks, will post solution if it works. Mike \\n </s>