Application note
Analogue signal out of range
All input channel signal levels are constantly monitored. If the signal is outside the specified limits, an alarm will be generated.
(See also: ChError.)
PD 640 (mA):
Signal too high:
Signal too low:
No load /Wire broken:
Alarm bit “SignalHigh” is set if the input signal exceeds 20 mA by more than 10%. (22 mA) (AnalogIn is held at 22 mA)
Alarm bit “SignalLow” is set if the input signal falls below 0 mA by more than 5%. (-1 mA) (AnalogIn is held at –1 mA)
4-20 mA mode only: A monitor of the input signal can be enabled to create an alarm “NoLoad” if the current falls below 3 mA.
This will indicate a no load or wire broken situation.
PD 641 / 643 (Pt100/Pt1000):
Signal too high:
Signal too low:
Alarm bit “SignalHigh” is set if the input signal exceeds 200 °C.
(AnalogIn is held at 200 °C)
Alarm bit “SignalLow” is set if the input signal falls below –100 °C.
(AnalogIn is held at -100 °C)
PD 642 / 643 (mV / thermocouple):
Signal too high:
Alarm bit “SignalHigh” is set if the input signal exceeds 100 mV by more than 10%, (110 mV) (AnalogIn is held at 110 mV), or exceeds the thermocouple’s specified range:
Type E: +1000 C
Type K: +1372 C
Type N: +1300 C
Type R: +1768 C
Type S: +1768 C
Type T: +400 C
Type J: +1200 C
Type B: +1820 C
(AnalogIn is held at high limit)
Signal too low:
Alarm bit “SignalHigh” is set if the input signal exceeds 100 mV by more than 10%, (110 mV) (AnalogIn is held at 110 mV), or exceeds the thermocouple’s specified range:
Type E: +1000 C
Type K: +1372 C
Type N: +1300 C
Type R: +1768 C
Type S: +1768 C
Type T: +400 C
Type J: +1200 C
Type B: +1820 C
(AnalogIn is held at high limit)
Related Topics
Notification
Limit alarms
Transmitter installation
AnalogIn calculation principle
Signal filter
Application note for PD 640 (mA)
Application note for PD 641 / 643 (Pt100 / Pt 1000)
Application note for PD 642 / 643 (mV / thermocouple)
Analogue modules
