HEIDENHAIN PWM 20 - Manual (Page 30)

November 2014 Software description 31
EnDat 2.2
Communication takes place continuously. However, there is no prescribed communication
pattern. Instead, every OEM determines the sequence of EnDat communication on his own.
 No universal “listening in” on the communication is possible.
 The monitor function is only possible, if the valuation numbers for online diagnosis
are included in data transfer. (The following controls support the monitor function:
TNC 620, TNC 640, iTNC 530 [as of NC-SW 34049x-04], iTNC 530 HSCI with diagnostic
function and DRIVE-DIAG.)
 Synchronization with communication may take some time.
1 Vpp
 No metallic isolation, if the measurement is conducted with the PWM 20 only.
 Metallic isolation is possible with the SA 100.
 The PWM 20 picks off the signals; without 120-ohm signal termination.
 The limit frequency is influenced by the test setup (adapter cable, etc.)
11 µApp
 The line is interrupted in feed-through mode, i.e. the PWM 20 has an 11 µApp receiver and
reproduces the (emulated) input signals at the 11 µApp output.
 The limit frequency is influenced by the test setup (adapter cable, etc.)
 Not yet approved for ATS V2.8. Signal errors may occur!
TTL
 Without PWT switchover:
The PWM 20 picks off the RS-485 signals, i.e. a standard RS-485 receiver without 120-ohm
termination is connected to the lines.
Example for machine axes with absolute encoders:
Determine the encoder ID with the PWM 20 before feed-through operation (no axis
movement required).
Automatic connection through entering the encoder ID is mandatory for feed-through mode at
axes with absolute encoders. However, the ID is not known and the encoders are not visible
under their covers.
The ATS software can read out and display the encoder ID.
Note
Automatic connection through entering the encoder ID is mandatory for feed-through
mode at axes with absolute encoders!
Incremental interfaces also permit manual connection by selecting the interface in
feed-through mode.
If the feed-through mode is not used, absolute and incremental encoders can be
connected manually.
However, automatic connection via the ID number is recommended!
DANGER
Testing cables for feed-through mode are not suitable for regular machine operation.
Due to the great variety of machine designs and their grounding variants it is not
possible to exhaustively test all testing cables.
It is absolutely necessary that you check the safe and proper function of the testing
cables for every test situation!
Uncontrolled axis movements cannot be ruled out when working with testing devices
and cables in feed-through mode.