Case 580SR Service Manual page 949

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TACHOMETER - ENGINE SPEED GAUGE
The tachometer accuracy should be less than or
equal ± 50 rpm. The above-specified tolerances
must be respected in all operating ranges (tempera-
ture, voltage, etc.). A stepper motor will drive the ta-
chometer. Needle calibration has never to be lost for
any external condition.
The message to be used is EEC1.
EEC1 message
0000
0001 => FFFD
Green field
Red field
FFFF
The behavior of the gauge in case of faulty sensor
will be to return to the parked position. Since this
signal is a function of the engine controller the ap-
propriate warning lamp and lamp will be illuminated.
During cranking, the needle movement shall be fro-
zen in order to inhibit any spurious movement of it.
ENGINE COOLANT TEMPERATURE GAUGE
A stepper motor will drive coolant temperature
gauge. The gauge accuracy should be less than or
equal 3%. Needle calibration has never to be lost for
any external condition.
Gauge
Gauge indication range +65 to +112 °C
Green field
Red field
The message to be used is engine temperature.
Engine temperature
message
00 => FD
FE
FF
SECTION 55 - ELECTRICAL SYSTEM
Gauge position
0 rpm
According to the value
0 - 2500 rpm
2500 - 3000 rpm
0 rpm
Temperature
+65 to +106 °C
+106 to +112 °C
Gauge position
According to the logic
above
Minimum value
Minimum value
An audible alarm must sound when the engine tem-
perature exceeds 106 °C.
If the sender is disconnected, the instrument must
go to 65 °C. Once the sensor is connected again,
the instrument must return to the correct position.
Both the movements have to be uniform.
The behavior of the gauge in case of faulty sensor
will be to return to the parked position. Since this
signal is a function of the engine controller the ap-
propriate warning lamp and lamp will be illuminated.
During cranking, the needle movement shall be fro-
zen in order to inhibit any spurious movement of it.
VOLTMETER GAUGE
The voltmeter will indicate the voltage of the vehicle
electrical system. This gauge will have three operat-
ing ranges: two reds and one green. One red range
will indicate low voltage. The other red will indicate
high voltage. The green range will indicate normal
operating voltage.
Z The bottom of the scale is 9 V.
Z Low voltage range 11 V or less. The pointer will be
±3° of the bold centerline indicating 11 V.
Z The normal operating range will vary between 11
and 16 V.
Z High voltage range 16 V or more. The pointer will
be ±3° of the bold centerline indicating 16 V.
Z The top of the scale will be 18 V.
A stepper motor will drive the voltmeter gauge. The
gauge accuracy should be less than or equal 3%.
Needle calibration has never to be lost for any exter-
nal condition. Loss of voltmeter sensor will be the
loss of the internal VCM A/D converter.
During cranking, the needle movement shall be fro-
zen in order to inhibit any spurious movement of it.
A/D accuracy is specified as ± 180 mV during self
test operation.
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