FranzPLC

FR S520S inverter reverse frequency problem

6 posts in this topic

Hi Guys,

I am using FR S520S 0 2k EC mitsubishi and when I run the motor forward, the frequency is the same with my analog output but when I run the motor in reverse the motor is just constant to 25Hz. I tried just a simple forward and reverse motor program and I just set the analog output in "monitoring watch" and the same problem. Motor forward frequency follows the analog output of plc while in reverse the frequency is just constant to 25 Hz. How can I solve this?

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Hi FranzPLC,

I don't know Mitsubishi frequency inverters (I use Schneider Electric) but I would say you have setup some Multispeed when you want to run the motor reverse. At first try to find, if any Multispeed is setup to 25Hz. If yes, then try to find if this Multispeed is used for the reverse instead of the signal on the analogue input (I suppose you use 0-10V or 4-20mA for forward - from PLC for example, or 0-10V from a potentiometer). I also suppose you use digital inputs for forward and reverse. If yes, try to find the settings for the digital input which is used for reverse. There will be probably setup the Multispeed. If you send the commands for forward and reverse from PLC via some serial link, it will be probably more complicated.

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Hi Franz,

Check Pr 63 how it is set up. It is for setting the STR terminal.  If set to 0, 1, 2 is used for low, medium or high speed. Reverse is set ---.

Good luck!

   
Edited by kraykov

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Hi Kraykov,

Can I only use the current input for one direction only orr It is possible for both? I tried 4(AU) in Pr. 63 but nothing happens. 

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How are you controlling STF/STR signals? Are they digital? And also, you are sending an analog signal for the frequency setpoint, or are you using a potmeter? Please let us know your complete setup.

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Hi Franz,
There is no problem using Terminal 4 to set the output frequency. Then configure the AU of another  terminal RL. 
When we want to work with the current input, we supply + 24V(terminal PC) to the terminal that we have configured as an AU (RL in my example ). It is necessary to use STF and STR terminals for START forward / START reverse.

Edited by kraykov

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