OPERATING MANUAL HPC & UMC4
Page 85 of 105
14.12 SELF-TEST function class
The SELF-TEST function class is comprised of the functions relating to the self-test of the sensor.
The diagnostic functions of the transmitter, which monitor the proper functioning of the electronics and the
software, are always active and cannot be switched off. The excitation current can be monitored in addi-
tion.
SELF-TEST
SELF-TEST
Sensor test
on / off
Sensor test
on / off
Max. deviation of
excitation
Max. deviation of
excitation
SELF-TEST
functional class
Sensor test
[off]
_______________
off
on
Max. deviation
020 %
Self-test
calibration
Self-test
calibration
Calibration
[no]
_______________
no
yes
Monitoring
sensor
Monitoring
sensor
S1 7749 S2 7812
E 1280
Display of
sensoramplitudes
Display of
sensoramplitudes
S1 090 S2 090 mV
112.8 Hz 12.8 mA
The excitation current of each sensor in the system individually depends on the sensor itself, the fluid and
the installation conditions. If the excitation currents changes while the fluid remains the same, conclusions
may be drawn for e.g. potential wear and tear, viscosity changes or air bubbles. The operator has the
possibility of defining a “normal state” (“Self-test calibration”) and setting the limit for a permissible devia-
tion. This function is deactivated in the device when delivered.
