PF525 Speed Ref 1 and 2 for two speeds

[ceilingwalker]

Hello All, I have a PF525 that the speed ref 1 is set to "Drive Pot" and speed ref 2 is set to "Keypad". I need to drive a motor at a rapid and a crawl speed, depending upon an input. What I would like to know is, since the PLC is only being used for on/off and not for speed, does the VFD treat those two speed ref methods differently so I can use one for high speed and one for low? Thank you

 

[JeremyM]

You could but you'd be assuming that the reference frequencies are reliably fixed. You could also try option 7 "Preset Frequency".

 

[ceilingwalker]

You could but you'd be assuming that the reference frequencies are reliably fixed. You could also try option 7 "Preset Frequency".

But this would take away from the ability of someone being able to adjust the speed on the fly, from the VFD, right? The customer doesn't have an OI for the PLC.

 

[JeremyM]

If that's a need, then presetting isn't the solution.

 

[sharkyh2o]

I use a Unidrive C much the same way you are describing. If you want an adjustment on the faceplate, set to pot and use a relay to cut off speed reference at low signal instead of prompting a preset, then set min speed for low. Drop Run FWD/REV for stop. I do not work very much with Powerflex so I am not familiar with parameters on that.
If you are looking for pot control from both use a relay and take the signal through a voltage divider and wire relay normally closed-full, normally open-divided using the existing preset signal.

 

[George Graziano]

Since it depends on an input. Input 1 could use Speed Ref 2 as the speed. Input 2 could use Speed Ref 3 as the command. Look at T62,T63,T65,T66,T67,T68. Also Look at P49,P51
George

 

[joseph_e2]

If you want the user to have two pots to choose from, you can use the drive pot for one reference and an analog input for the other with the analog input wired to an external pot. The digital input would select which reference to use.



A simpler but less smooth option is to have the drive always look at the analog input but have 2 external pots. A relay/switch can connect/disconnect the appropriate pot to the analog input. I'm not really a fan of this option, but I've seen it done successfully in the past.

 

[ceilingwalker]

Since it depends on an input. Input 1 could use Speed Ref 2 as the speed. Input 2 could use Speed Ref 3 as the command. Look at T62,T63,T65,T66,T67,T68. Also Look at P49,P51
George

But there is no operator interface (HMI) that would allow a change to be made that way, if I am understanding what you're saying that would be a requirement? I am trying to find a way to give them control of the two speeds and I am not convinced what I am thinking will even work.

 

[joseph_e2]

Take a look at the user manual. Chapter 3, terminal block group.



You could set t062 to identify TermBlk 02 as Speed Ref 2, which is parameter P049. You would set P049 to, for instance, 1, "Drive Pot". You would then set t063 so TermBlk 03 chooses Speed Ref 3, which is P051, which you could set to 2 (Keypad Freq), or 5 (0-10V input) or etc....


Then, a selector switch could energize either input 2 or input 3 to pick which speed reference was active.

 

[ceilingwalker]

Take a look at the user manual. Chapter 3, terminal block group.



You could set t062 to identify TermBlk 02 as Speed Ref 2, which is parameter P049. You would set P049 to, for instance, 1, "Drive Pot". You would then set t063 so TermBlk 03 chooses Speed Ref 3, which is P051, which you could set to 2 (Keypad Freq), or 5 (0-10V input) or etc....


Then, a selector switch could energize either input 2 or input 3 to pick which speed reference was active.

Got it! Thanks folks for your help. :site: