Siemens SINUMERIK 840D sl Function Manual page 342

Compensations (K3)
5.2 Temperature compensation
Activation
The following conditions must be fulfilled before temperature compensation can be applied:
1. The option must be enabled.
2. The compensation type is selected (MD32750 $MA_TEMP_COMP_TYPE).
3. The parameters for the compensation type are defined.
4. The axis is referenced:
As soon as these conditions are fulfilled, the temperature compensation value for the current
position actual value is added to the setpoint in all modes and the machine axis is traversed.
If the reference position is then lost, e.g. because the encoder frequency has been exceeded
(DB31, ... DBX60.4 or 60.5 = 0), compensation processing is deactivated.
Temperature fluctuations and parameter changes
Since the approximated error line applies only to the instantaneous temperature value, the
parameters of the error lines that are newly generated when the temperature rises or falls
must be sent to the NCK again. Only in this way can expansion due to heat be compensated
for effectively.
When temperature T changes, the parameters which are temperature-dependent, i.e. (K
tanβ and P
synchronized action.
It is thus possible for the machine-tool manufacturer to represent the mathematical and
technological relationship between the axis positions and temperature values via the PLC
user program and thus calculate the various parameters for the temperature compensation.
The temperature parameters are transferred to the NCK with variable Services (FB2 (GET)
"Read data" and FB3 (PUT) "Write data").
For more information on handling and parameterization of FB2 and FB3 see:
References:
/FB1/ Function Manual, Basic Functions; Basic PLC Program (P3)
Monitoring
MD32760 $MA_COMP_ADD_VELO_FACTOR
(velocity violation caused by compensation)
The axial machine data above can be set to limit the maximum compensation value that is
added to the specified velocity value in each IPO cycle.
This machine data limits the maximum gradient of the error curve. If the maximum gradient is
exceeded, the compensation value is limited in the control.
Smooth the compensation value
To prevent overloading of the machine or tripping of monitoring functions in response to step
changes in the above parameter settings, the compensation values are distributed among
several IPO cycles by an internal control function as soon as they exceed the maximum
compensation value specified for each cycle in the following machine data:
MD32760 $MA_COMP_ADD_VELO_FACTOR
(velocity violation caused by compensation)
342
DB31, ... DBX60.4 or 60.5 =1 (homed/synchronized 1 / 2)
) also change and can thus always be overwritten by the PLC or by means of a
0
Function Manual, 01/2008, 6FC5397-1BP10-3BA0
,
0
Extended Functions