Galvanic Applied Sciences 943-TGX-CE, Operation Manual

Page: 144 / 151

Revision 4 144 April 2020
2. The value in the Zero field must be set to 4, and the value in the Span field must be
set to 20.
3. Connect a multimeter set to milliamp measurement to the analog output to be
calibrated. The analog outputs are all on terminal block P3 of the IO board. The
terminals for each analog output are clearly marked on the board. Refer to Figure 90.
Figure 90: Analog Output Terminal Block P3
The analog outputs on the IO board are loop powered, so an external power
supply must be provided. The multimeter must be placed in SERIES with the
current loop. When the multimeter is connected correctly, a green LED
above the analog output wiring connection on the IO board will illuminate
to show that the current loop is closed and loop power is being provided,
as indicated in Figure 91.
4. Press the Output Zero button. The output current from the analog output will change
to approximately 4 mA.
5. Enter the reading from the meter in the
Meter Reading field under the Zero heading
and press the Auto Cal button. This will adjust the Zero output to exactly 4 mA. If the
meter reading is still not exactly 4 mA, repeat the process.
6. Press the Output Span button. The output current from the analog output will change
to approximately 20 mA.
7. Enter the reading from the meter in the Meter Reading field under the Span heading
and press the Auto Cal button. This will adjust the Span output to exactly 20 mA. If
the meter reading is still not exactly 20 mA, repeat the process.
8. The analog output is now calibrated. Press
Capture to save the calibration to the
board.
9. Test the output by entering the desired mA output in the Test(mA) field and then
pressing the Output Test button. This will force the analog output to generate the
entered value. In this way the analog output loop can be tested at several readings
such as 0, 25, 50, 75 and 100 % of scale (4, 8, 12, 16 and 20 mA). It is advisable that
this test be done in conjunction with control room staff to ensure the correct readings
are being received not only at a multimeter connected to the analyzer but also at the
DCS.
Loop power available, current
loop
complete indicator
LEDs, one per analog output.