Hi all,

I am new to motion control using S7-1200. The scenario of my problem is as shown below.

"I have a stepper motor with function moving repeatedly from position A to position B and back to position A. Some error happen in the machine and I pressed the emergency stop button which disable the stepper motor.

Unfortunately, at the same time during the error, the motor touches the low limit switch which trigger the limit switch error. The problem now is, after I release the emergency button and enable the motor, I unable to trigger the motor to move away from the limit switch because of the limit switch error.

I understand that disabling the motor will reset the Homed status of the motor. But the problem now is I can't even home the motor due to the limit switch error."

Any suggestion or setting that I can make to handle this problem? Thank You.

Currently I have no choice but disabling the motor and manually move the motor away from the limit switch, but I believe this is not a long term way to solve this problem.

Hi, I am using S7-1214C DC/DC/DC, 6ES7 214-1AG40-0XB0, firmware V4.2.

BTW, I tested with my program:

1. I manually move my motor to touch the limit switch.

2. After the 'low limit switch' alarm, I disable the motor with E-Stop.

3. Then enable the motor.

4. Reset the motor with 'MC_Reset'.

5. Home the motor and the motor working just as normal (Back to home and 'limit switch alarm' clear) 

I suspect maybe there is something wrong with my program sequence in handling the limit switch alarm during auto sequence. However, I still hope to look for any suggestion in handling this type of error. Thank You.