SomoZao

Good morning everyone,

I would like to share my situation with you.

I have a pump that operates in two modes. When it starts up, I need it to run at its maximum capacity for a short time (it starts working with water) to reach a certain pressure in the line. As soon as I send a signal, it switches to PID control (it starts to handle a product that is not water).

It performs this perfectly, but with some issues. For it to work properly, I need to ramp the motor up to 90 Hz (the manufacturer instructed me to do so), and then when it switches to PID control, due to the higher density of the product, the frequency drops to 20-30 Hz and stabilizes there (arround 500-600 rmps).

The drive is a G120C PN and the motor is 50 Hz, 1450 1/min, 400V, 3 kW, 6.26A cos 0.8.

To change the frequency, I set the p310 parameter to 100 Hz (I actually use the assistant, so I'm not sure if this is done correctly).

My first question is: The calculation it makes for the operating speed is no longer correct, right? If it shows 1450, it's not real, is it?

After a few hours of operation, I get the F7011 error, which I know is a temperature error. The motor itself is not hot, and I can't install the temperature sensor because the analog input of the drive is used for PID control, so I understand that this error is due to an internal calculation by the drive, right?

Could this be solved by adding forced ventilation? Or will it continue to make the calculation and trigger the fault?

I have also noticed that the p1082 parameter is displayed in rpm and not in Hz like for many of you, and I'm not sure if this could affect anything.

I don't usually work with Siemens drives and it's driving me a bit crazy.

Thank you all very much.

 Parameter P0310, this sets the motor rating frequency, from the nameplate. Setting this as you have will cause incorrect readings, and operation; hence the over heat.

The setting for the speed / Hz, should come from an analogue input or serial, USS or Profi>

Yes these devices refer to rpm rather than Hz which is not so easy to use, the code being sourced from servo drives, so there is no easy switch to get Hz, and you are not missing anything.

I have attached a drawing for PI control, whilst this refers to 'stairwell pressure control', the configuration is similar, and should help with getting the control correct.

Tractor