EN.IO.APC.APR.ALW
Revision 02.A.005/2020.06
29
Figure 13
. Set range current, saturation currents, alarm currents of transmitters in standard or Exi version.
1 - Set 4
…20 mA current area is corresponding to setpoint 0...100% of the process output.
2 - Lower saturation current of 3,800 mA for NAMUR mode.
3 - Lower saturation current of 3,900 mA for NORMAL mode.
4 - Upper saturation current of 20,500 mA for NAMUR and NORMAL mode.
5 - Alarm current area AL_L<3,650 mA for internal diagnostic alarms.
6 - Alarm current area AL_H>21,500 mA for internal diagnostic alarms.
The transmitter diagnostics continually tests the environmental parameters:
−
temperature of the pressure measurement structure sensor;
−
temperature of the ADC transducer converting the electric signal from the pressure sensor to
the digital value of measurement;
−
temperature of the CPU structure (transmitter's main microcontroller). For transmitters in Exd or
Exi/Exd version, if the operating temperature limits are exceeded, the diagnostics will trigger an
alarm I_AL<3,600 mA. Temperature return to permissible range of the transmitter operation will
result in deactivation of the diagnostic alarm mode and return to normal operation. For transmit-
ters in standard or Exi version, if alarms from 2, 3 and 4 process variable (temperatures) are
enabled, when the transmitter operating temperature limits are exceeded, the diagnostics will
trigger an alarm depending on the settings AL_L<3,650 mA or AL_H>21,500 mA. Temperature
return to permissible range of the transmitter operation will result in deactivation of the diagnos-
tic alarm mode and return to normal operation.
The transmitter diagnostics continually tests the pressure process parameters:
−
if the pressure/differential pressure value increases above 50% of the base range width from
URL point reaching the UPL point, the diagnostics of transmitter in Exd or Exi/Exd version will
trigger an alarm I_AL<3,600 mA. The return of the pressure/differential pressure below the UPL
point will result in deactivating the alarm and returning the transmitter to its normal operation. In
case of transmitters in standard or Exi version, if the pressure/differential pressure value in-
creases to the upper limit of ADC measurement converting transducer, reaching the USAL
point, the diagnostics will trigger an alarm depending on the configuration AL_L<3,650 mA or
AL_H>21,500 mA. The return of the pressure/differential pressure below the USAL point will re-
sult in deactivating the alarm and returning the transmitter to its normal operation;
−
if the pressure/differential pressure value decreases below 50% of the base range width from
LRL point reaching the LPL point, the diagnostics of transmitter in Exd or Exi/Exd version will
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