Hello,

In SIMATIC S7-1500(T): Basics of axis control with technology objects and approach t... - ID: 109779884 - Industry Support Siemens I read the following:

Simatic S7-1500(T): Basics of axis control with TO and approach to axis optimization

Axis setpoint value calculation and output The application clock limit is the beginning of the Motion Control application cycle (MC cycle). The target positions (reference variables) for the next MC cycle are calculated in the motion control in MC-Interpolator. In the next MC cycle, the position control for the axes and the speed setpoint for the associated drives are calculated in MC-Servo. At the end of MC-Servo (or MC_PostServo), the outputs are written to the drive (fine interpolation in the drive).

Does this also mean: If I read out the value TO.ActualPosition in MC-Interpolator I get the old ActualPosition from the previous cycle?

If I read out TO.Position (setpoint) in MC-Interpolator or MC-Servo I should get the same value?

Greetings

AutoGen_5308265

Does this also mean: If I read out the value TO.ActualPosition in MC-Interpolator I get the old ActualPosition from the previous cycle?

Technically speaking you (i.e. your code) can't read anything in MC-Interpolator. You can do it in MC-PreInterpolator and there you get the most recent ActualPosition received (i.e. position supplied by the preceding MC-Servo). Of course this position is past position.

What are your concerns actually ?

 Thanks for the reply!

So in MC-PreInterpolator you use the previous position of the servo, in MC-PreServo I would have the actual position the servo is at that moment (with delay of the bus communication)?

I need to check the status of a sensor at a certain position of the servo, its high precision. Is it best to do this in MC_PreInterpolator or MC-PreServo? Or won´t it matter that much.

Every servo clock cycle (4ms) the position change is 0,48mm and the modulo is 12mm. 

jacek d

 

AutoGen_5308265

Does this also mean: If I read out the value TO.ActualPosition in MC-Interpolator I get the old ActualPosition from the previous cycle?

Technically speaking you (i.e. your code) can't read anything in MC-Interpolator. You can do it in MC-PreInterpolator and there you get the most recent ActualPosition received (i.e. position supplied by the preceding MC-Servo). Of course this position is past position.

What are your concerns actually ?