Sinamics G120, Incremental encoder problem while reversing direction

I have two SINAMICS G120 (CU250S-PN and PM240-2 (1,1kW)). I want to drive them in diferent directions. When I do the rotating measurment with encoder in CW direction everything works fine. For the second drive I changed the parameters p1820 to ON(so that I reversed the phases and changed the direction of the motor) and p0410 (so that I inverted the encoder position and speed). I can preform stationary and rotating measurment but when I try to preform rotating measurment with encoder an error appears ("Zero mark failed"). Bellow are some examples for easier understanding of the problem.

Motor and encoder not inverted (works OK)

Motor inverted and encoder not inverted(does not work OK) error at cca. 24s

Motor and encoder invrted (does not work OK) error at cca 12s

I also tried doing motor optimization in normal CW direction and everything works fine, then I tried to reverse the direction through Technology objects but I get the same error as before.

I am using a TTL encoder HS25F-62-R10-BS-1024-ABZC-15V/V-SM12-S. I am connected over X2100 port.

The wiring on the encoder side:

the wiring on the CU250S side:

I have the same problem on both motors if I try to reverse their direction to CCW. I also tried with a different motor and encoder and I could reverse the direction with out a problem.

I would appriciate any help.

Regards

Hi,

please do not use p1820 to change the direction - this only changes the output phases to the motor but not the encoder direction.

Instead you should change p1821 to CCW - this changes both output phases and encoder direction.

Thank you for your reply. I can not find the parameter p1821.

Regards

Ahh you are right, I just knew this parameter from SINAMICS S120 and didn't know it is not existing on G120. 

So I looked up p1820 in the list manual and it says that you might also need to change p410 -> encoder actual value direction so that it fits together. In p410 there should be 2 bits: 

p410.0 = invert speed actual value

p410.1 = invert position actual value 

Without being able to try this out myself I would try to set p1820 = 1 and then also p410.0 and p410.1 = 1.

Thank you for your reply.

I already tried what you suggested, but it did not work I still get the "Zero mark failed" error.

I guess both encoders are faulty or the wiring is not correct. I wrote the the manufacturer and will be posting if the issue gets resolved.

Regards

ok.

Otherwise what about just changing the speed setpoint to negative values for one of the drives? So leave p1820 = 0 and just move in the other direction by negative speed setpoints? Probably not what you wanted, but just to mention it.

I already tried that, if I try to jog backward in commisioning i get the same error as before.

Regards

I got a reply from the manufacturer. They said the wiring is correct but the encoder is faulty. I ordered a new one and will follow up as soon as soon as I know anything.

Regards