92
Monitoring of DC analogue
measurements
Chapter 11
Verifying settings by secondary
injection
11
Monitoring of DC analogue measurements
A stabilized direct current generator and mA meter with very high accuracy for mea-
surement of direct current is needed in order to test the dc measuring module. The gen-
erator operating range and the measuring range of the mA meter must be at least
between -25 and 25 mA.
Prepare the terminal for verification of settings as outlined in section “Preparing for
test” in this chapter. Connect the current generator and mA meter to the direct current
input channels to be tested.
Procedure
1.
Consider the need to block output signals.
2.
Check that the values presented on the HMI module corre-
sponds to the magnitude of input direct current within the lim-
its of declared accuracy.
The service value is available under the submenu:
Service Report/I/O/Slotnm-MIMx/MIxy-Value
3.
Check the operation of ADBS or IDBS function when applica-
ble. Compare with the expected values.
The operation of ADBS or IDBS function can be checked sepa-
rately with the setting of RepInt = 0. The value on the HMI must
change only when the changes in input current (compared to the
present value) are higher than the set value for the selected dead
band.
where:
nm
represents the serial number of a slot with tested mA input module
x
represents the serial number of a mA input module in a terminal
y
represents the serial number of a measuring channel on module x.
