HEIDENHAIN PWM 20 - Manual (Page 29)

30 HEIDENHAIN ATS Software User's Manual
5.2.1 Feed-through mode
"´Feed-through" mode means connecting the PWM 20 into the control loop of an NC-controlled
machine.
For diagnosing, the PWM 20 can be integrated into the control loop of an NC controlled
machine tool via adapter cables at the encoder input X1 and the encoder output X2.
For the feed-through mode the power supply must be switched to the subsequent electronics
in the ATS software.
Set the checkmark in feed-through mode only.
If no subsequent electronics is connected, the encoder is not powered (error message).
The feed-through mode is supported as of the software version 2.6. We recommend always
using the most recent software version (see www.heidenhain.de).
The feed-through mode cannot be used for all interfaces supported by the ATS.
In principle, the following interfaces allow for feed-through mode:
EnDat, Fanuc, Mitsubishi, 1 Vpp, TTL, 11 µApp
EnDat/Fanuc/Mitsubishi
 Metallic isolation is possible with the service adapters SA 100 and SA 110.
 No metallic isolation, if the measurement is conducted with the PWM 20 only.
 For encoders that also support incremental signals, the incremental signals can now also be
displayed and evaluated.
EnDat 2.1
Normally, the only communication over the EnDat interface takes place during the start-up stage
of the NC (interrogation and transfer of the absolute position data):
 "Listening in" on the EnDat communication is not possible. (The synchronization time is too
short for the PWM 20.)
 The 1 Vpp signals A and B can be displayed.
Note
SIEMENS NC controls currently use EnDat 2.1 with A/B signals and do not support the
monitor function!