Hirschmann PAT DS 85/0002 - Length Theory

© Hirschmann Rev. G 10/05/15 190166_G.DOCXG
9
6 LENGTH THEORY
The system measures the length of the main boom of the machine with a length sensor. The length
sensor is contained within the cable reel, located in the base of the main boom.
Block Diagram
Radio A2B Option:
Hardwired A2B Option:
The signal runs from the length sensor to the CAN-Bus converter board, located in the angle sensor
box. From there, it travels as digital information on the CAN-Bus to the pressure transducer, which
acts as a T-connector to the main CAN-Bus running to the central unit.
So, what do you do when you are having a problem with your length read-out?
Start by verifying the length display. Refer to the section “Troubleshooting A Sensor Problem Using
The Display” to call up the sensor signal on your console display. The CAN-Bus is digital and as such
will either transmit the signal correctly or not at all. If your readings are off, you have to determine
what is causing the problem. Start by checking the length cable tension, the cable reel has 3-5 turns
of pre-loading on the reel.
Go back to your indication screen and compare indicated and actual length again. If the indicated
length varies significantly from your actual length (more than 0.3 feet), the length sensor might be bad
and needs to be exchanged. Note, however, that the error could be in the converter board.
The length sensor has a potentiometer built in that is driven by a gear drive from the cable drum. As
the length changes, the cable drum will turn and with it the potentiometer’s axle. The converter board
supplies a voltage of about 4.7V to the length potentiometer and in return monitors the output voltage
of the potentiometer. The terminal used is X20. The length sensor is connected as follows:
Pressure Transducer
DS 85
Console/
CU
Cable Reel
Length
Sensor
CAN-Bus
Converter
Pressure Transducer
DS 85
Console/
CU
Angle Sensor Box
Length
Sensor
CAN-Bus
Converter