HEIDENHAIN PWM 20 User Manual
Page 21
22
HEIDENHAIN PWM 20 Testing Package – Cable and Connection Technology
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.
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.
Note
SIEMENS NC controls currently use EnDat 2.1 with A/B signals and do not support the
monitor function!
DANGER
The test cables for feed-through operation are not intended for regular machining.
Due to the great variety of machine designs and consequently very many grounding
variants, not all testing cables can be checked out to a tee.
It is absolutely necessary that you check out the safe and proper function of
respective testing cables for every test situation!
Uncontrolled axis movements cannot be ruled out when working with testing devices
and cables in feed-through mode.