Mitsubishi MELDAS MDS-C1 Instruction Manual page 165

(2) Adjusting the gap
1) Confirm that the detection gears are not rotating. The sensor could be damaged if the gap is
adjusted while the gears are rotating.
2) Loosen the sensor fixing screw with the sensor fixed on the sensor installation seat.
3) Using a clearance gauge, adjust so that the gap between the sensor detection surface and the
detection gears' circumference is 0.15±0.01mm.
4) The sensor can be moved up and down or turned when the sensor fixing screw is loosened.
Position the rotating direction to match the marking line drawn on the sensor and installation
seat.
5) When done adjusting the gap, apply a locking agent on the sensor fixing screw, and then fix
the sensor.
6) After fixing the sensor, check the gap again. If operation is carried out with an excessively
small gap, the sensor and gears could contact, and the sensor could be damaged.
7) Faults could occur if an excessive external force is applied or if the sensor detection surface is
damaged.
(3) Checking the A phase and B phase output signal
Check the output signal waveform by measuring the signals of the check terminals on the PCB
with the DC range of the synchroscope.
A phase output signal........ Across A-G
B phase output signal........ Across B-G
The PLG reference speed when confirming the output signal waveform differs according to the
number of output pulses. Refer to the following table for the reference speed for each number of
pulses. If operation is not possible at the reference speed, operate at a low speed within the range
in which the waveform can be confirmed.
Check terminal function
Check
Signal name
terminal
A A phase
B B phase
Z Z phase
G Ground
The output signal waveform is confirmed when the motor is run in the forward direction and reverse
direction. The rotation directions are defined below.
During forward run ... When the detection gears are rotating in the clockwise direction looking
During reverse run ... When the detection gears are rotating in the counterclockwise direction
The normal A and B phase output signal waveform when running at the reference speed is shown
below. If the output signal waveform is not as shown below, refer to the next section "(4) Adjusting
the A and B phase output signal" and adjust.
Voltage [V]
A phase B phase
1.45 ~ 1.55
0
-1.45 ~ -1.55
A phase/B phase output signal waveform
during forward run
3. Setup
Reference speed for A and B phase output signal confirmation
Number of detection
gear teeth
128
180
256
512
from the sensor lead side.
looking from the sensor lead side.
Time
3 - 86
Number of A and B
phase pulses
128
180
256
512
Voltage [V]
1.37 ~ 1.63
0
-1.37 ~ -1.63
A phase/B phase output signal waveform
during reverse run
Reference speed for
signal confirmation
3600 r/min
2500 r/min
1800 r/min
1200 r/min
B phase A phase
Time