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Diagnostics
The keypad supports the Diagnostic Trouble Codes as specified in SAE J1939-73. The
corresponding diagnostic message PGNs (DM1, DM2, DM3) can be found in the K-Matrix and
are specified if they need to be read via read command or are submitted cyclically. The error
codes are listed in the K-matrix too and are shown in the table below:
Error code Name
Description
0x7F000
No error
0x7F250
Overvoltage
Input voltage exceeds 33 volts
0x7F250
Undervoltage
Input voltage falls below 8 volts
0x7F030
Overtemperature
warning
Keypad temperature exceeds 100°C
0x7F040
Overtemperature
error
Keypad temperature exceeds 125 °C
0x7F050
Temperature
sensor defect
Implausible temperature values are measured
0x7F070
Button stuck
Button is pressed longer than the time value defined in object
0x2101 (default value: 10s)
0x7F110
Button pressed at
startup
One or more buttons are pressed during power-on-reset
0x7F080
Button unstable
Switching element bounces excessively; reason: switching
system worn out
0x7F100
Button out of range Resistance of the switching system reach upper limit; reason:
switching system worn out
0x7F120
Button crosstalk
Button was detected as pressed although a other button should
be pressed; detection over cyclically detuning the voltage divider
of each button; reason: incoming moisture in the keypad
0x7F130
Button test low
Cyclically detuning of voltage divider of each button returns
implausible values; reason: incoming moisture in the keypad,
switching system worn out
The current module temperature and the current voltage is measured by the keypad and can
be read via a read request according to chapter 9.4.
9.6.1
Current Module Temperature
The object for storing the temperature is object number 200 (0xC8) and it is also cyclically
transmitted by the Process Data Prop B as described in chapter 9.5.2. The value transmitted
is a hexadecimal value. To calculate the actual temperature it has to be transferred into decimal
and 40 needs to be subtracted.
