Checking Position And Speed Encoders - HEIDENHAIN iTNC 530 Service Manual

17.4 Checking Position and Speed Encoders

PWM 9 The electric functioning of an encoder is measured using a phase angle measuring unit
(PWM), an oscilloscope and an impedance tester (see Operating Instructions, Encoder
Diagnostics Kit PWM 9).
Adapter Various adapters have been developed to permit PWM8 measurement of the different encoder
signals (11 µApp, 1 Vpp, TTL) at iTNC 530. You will find a connection diagram of the adapters
and ID numbers in the PWM 9 operating manual.
Internal In the internal oscilloscope (See "Integrated Oscilloscope" on page 8 – 49) of the iTNC 530
oscilloscope the analog encoder signals of the position encoder are recorded:
Position: A (0° signal) and position: B (90° signal)
The signals in the integrated oscilloscope are always displayed in the unit mV, independent of
the type of encoder connected (1 Vpp or 11 µApp).
These displayed signals are the image of the input on the counter IC inside the control. Therefore
certain amplification factors and an offset voltage of 2500 mV must be regarded. --> The signal
amplitude in mV oscillates symmetrically about 2500 mV and must therefore be divided by
the corresponding amplification factor:
May 2006
Note
Solely the incremental signals (A, B or I1, I2) of position encoders can be recorded and this
only if they are not connected to an MC (not CC).
Reference signals and EnDat signals cannot be displayed!
A phase angle measuring unit is required for an accurate tracing of the signals.
Current signal Oscilloscope display [mV] / 284 = encoder signal at input [µA]
11 µApp: e.g.: 3124 [mV] / 284 = 11 [µA]
Voltage signal 1Vpp: Oscilloscope display [mV] / 3480 = encoder signal at input [V]
e.g.: 3480 [mV] / 3480 = 1 [V]
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