Troubleshooting Principal Parts - Mitsubishi Electric e Series Service Handbook

[ IX Troubleshooting ]

[3] Troubleshooting Principal Parts

High-Pressure Sensor
-1- High pressure sensor (63HS)
1. Perform a check while comparing the detected pressure by the high pressure sensor with the high pressure gauge
pressure.
When the digital display changeover switch (SW4) is set as follows, the detected pressure of the high pressure sen-
sor is displayed on the LED (LD1).
(1) Compare the gauge pressure and the pressure displayed on the LD1 while the operation is stopped.
1) When the gauge pressure is about 0 - 0.098 MPa → Internal pressure drop due to gas leakage
2) When the pressure displayed on the LD1 is about 0 - 0.098 MPa → Check the connector for contact failure and disconnection
and see (4)
3) When the pressure displayed on the LD is 4.15 MPa or above → See (3)
4) When any of 1) to 3) do not apply, compare the pressure during operation → See (2)
(2) Compare the gauge pressure and the pressure displayed on the LD1 during operation. (Compare using MPa unit)
1) When the difference in pressure is within 0.098 MPa → The high pressure sensor and the main circuit board are normal
2) When the difference in pressure is over 0.098 MPa → The high pressure sensor is malfunctioning (characteristic deterioration)
3) When the pressure displayed on the LD1 does not change → The high pressure sensor is malfunctioning
(3) Remove the high pressure sensor from the main circuit board and check the pressure displayed on the LD1.
1) When the pressure displayed on the LD1 is about 0 - 0.098 MPa → The high pressure sensor is malfunctioning
2) When the pressure displayed on the LD1 is about 4.15 MPa → The main circuit board is malfunctioning
(4) Remove the high pressure sensor from the main circuit board, short-circuit 2-3 of the connector (63HS), and check
the pressure displayed on the LD1.
1) When the pressure displayed on the LD1 is 4.15 MPa or above → The high pressure sensor is malfunctioning
2) When 1) does not apply → The main circuit board is malfunctioning
2. High pressure sensor structure
The high pressure sensor consists of the circuit shown on the right.
When 5 VDC is applied between red and black, a voltage corre-
sponding to pressure is output between white and black, and this
voltage is taken in by the microcomputer.
The output voltage is 0.071 V per 0.098 MPa.
* The pressure sensor main body side is to be connected to a con-
nector.
The pin number of the connector is different between the pressure
sensor main body side and the main circuit board side.
Main body side
Vcc Pin 1
Vout Pin 2
GND Pin 3
ON
1 2 3 4 5 6 7 8 9 10
HWE20010
ON
1 2
Main circuit board
side
Pin 3
Pin 2
Pin 1
The figure at left shows that
the switches 1 through 5 are set to
ON and 6 through 10 are set to OFF.
3 4 5 6 7 8 9 10
Connector
- 119 -
(Also possible with the display monitor)
Output voltage (V)
Pressure 0 - 4.15 MPa
Vout 0.5 - 3.5 V
0.071 V / 0.098 MPa
GND (Black)
Vout (White)
Vcc (5 VDC) (Red)
GB