Hi


I have a question.

I know how other motion controllers are positioned on the home point. These move from the approximation sensor towards the home sensor and immediately reduce speed (velocity) so when the proximity sensor is off, the home point receives the Z signal from the encoder, and this is the high precision reference home position.


When using the S7-1200, how can you find high precision without that Z signal from the encoder but using only the proximity sensor to the home reference point?.

Thanks

cody_master

It's only reducing the velocity and activating one more time the approximation sensor. Is it correct?

 Seems the only way, straightforward. What it matters is how you wish to approach: in negative way, positive way - this implies that your ref sensor is located near the end travel, once the ref position is determined your axis should move away from it at home position. Alteranatively you can place the sensor in between two endstop sensors, you may check the box with reversal: if you set negative direction and the endstop switch is overtraveled, the procedure will switch to positive direction and it will change direction when ref. sensor will be detected.
For the sake of simplicity, if you don't need end stop sensors, you may place a ref sensor close to end and choose the direction. It depends on final reference velocity and sensor switch distance precision, usually the mechanical switches are very precise, but they tend to wear and they also allow only limited speed of crossing (the angle/shape of ramp is important, too ), so it is placed at the end, out ov travel zone.