HEIDENHAIN TNC 410 M Technical Manual page 49

HEIDENHAIN recommends:
Please use a signal amplifier for the unit bus with ID 753 170-51 on the
machines likely to be affected by the problem (above-mentioned
preconditions)! The use of such a signal amplifier makes it possible to prepare
the signals of the unit bus so that the fault does not occur.
The signal amplifier for the unit bus X79 must be plugged onto any available
connector on the unit bus ribbon cable (mounting instructions are included
with the signal amplifier). If, contrary to expectations, there is no available
connector on the unit bus, a longer unit-bus ribbon cable must be used. Should
this be the case, please get in touch with your contact partner at
HEIDENHAIN.
Ensure during installation that the insulating strip on the back of the signal
amplifier is not coming off or damaged.
Please keep in mind that only one signal amplifier for the unit bus may be used
on any X79 unit bus!
Further procedure:
Starting immediately, the signal amplifier for the unit bus will be included with
the CC 61xx as an accessory. Please use the signal amplifier on all machines
with HSCI control systems as described above. Machines already shipped
must only be retrofitted with the signal amplifier if the fault described above
occurs.
The signal amplifier for the unit bus must not be used on systems with
MC 42x and CC 42x.
If you need assistance in evaluating the situation, please contact the
responsible HEIDENHAIN service agency.
1 – 2 HEIDENHAIN Technical Manual for Inverter Systems and Motors