Optimizing The Position Controller; Checking The Direction Of Traverse And Counting Direction; Optimizing Kv Factors For The Position Controller - HEIDENHAIN TNC 415 Technical Manual

3.3 Optimizing the position controller

The position controller is trimmed in the same way as with the TNC 415. This rule applies for
operation in the trailing error mode and with feed precontrol. Please note the description in Chapter
4, "Machine Integration", and the following information.
Evaluation of reference marks
After trimming the speed controller, the desired evaluation of the reference marks must be entered
in MP1350.

Checking the direction of traverse and counting direction

The directions of traverse and counting must be checked again after the linear encoder for the
position controller is activated with MP1951. The position controller is matched to the machine
coordinate system with the following machine parameters:
- MP1040 Polarity of nominal speed value in positive direction of traverse
- If the counting direction of the axis is correct but motion is wrong, then MP210 (counting direction)
must be modified.
Start axes with direction keys for a short period and correct the input values for polarity or counting
direction if necessary.

Optimizing Kv factors for the position controller

With digital drive control the limits and/or ideal values are more dependent on the drives and the
machine's mechanical systems than with previous control systems. In terms of the control principle,
it is possible to work with high Kv factors and very small trailing errors. It is important to remember
that the mechanical load on the machine will be greater.
Additional selectable Kv factors have been introduced for this reason, and they are stored in
machine parameters MP1515.x and MP1815.x. Reduced Kv factors can be used for general milling
work without great demands on accuracy at higher feed rates.
Delayed shutdown of speed controller in EMERGENCY STOP
Because the speed controller is integrated in the control system, the controlled axis runs down
when the torque signal is turned off. For this reason the control system continues to be active for a
certain time (MP1980) in an EMERGENCY STOP condition and outputs a torque. The time entered
for this must be matched to the relevant drives and machine.
The axes must be stopped immediately by external holding brakes if the control fails and no braking
torque can be output.
01.98 TNC 407/TNC 415/TNC 425 3 Machine interfacing 11-15