56
The
Engineering Calibration
section is used to associate concentration values with the milliamp
signal output. The
mA
Zero
field is used to enter the milliamp value that is output when the analog
output is outputting a zero signal; the default value for this field is 4mA. The
mA
Span
field is used
to enter the milliamp value that is output when the analog output is outputting a full-scale signal;
the default value for this field is 20mA. The
Engineer Zero
and
Engineer Span
fields are used to
enter the concentration values for a zero output (typically 0ppm) and a span output (typically the
full scale value). Once the desired values have been entered into these fields, the
Capture
button
must be clicked to save these values to the board.
The
IO Board Calibration
section is used to calibrate the analog output so that it outputs a zero
signal when a zero signal is required and a span signal when a span signal is required. In the
Scaled
Value
fields for
Zero
,
Span
, and
Fail-safe
, the current outputs associated with each of these points
should be set (default values are 4mA, 20mA, and 3mA respectively). The
Raw Value
fields below
each of the Scaled Value fields shows the raw hardware output value for zero and span. To
calibrate the analog output, follow the procedure below:
1.
Connect a multimeter or other current measuring device to the analog output to be
calibrated.
2.
Click on
Output Zero
and ensure that the meter reads approximately 4mA.
3.
Enter the exact reading on the multimeter into the
Meter Reading
field for Zero. Press
Enter. The number displayed in the
Raw Value
field for zero should change and the
current reading on the multimeter should now be exactly 4.00mA.
4.
Click on
Output Span
and ensure that the meter reads approximately 20mA.
5.
Enter the exact reading on the multimeter into the
Meter Reading
field for Span. Press
Enter. The number displayed in the
Raw Value
field for Span should change and the
current reading on the multimeter should now be exactly 20.00mA.
6.
Press
Capture
to save the analog output calibration to the IO board.
Once the analog output has been calibrated, the output can be tested by using the
IO Board Test
section. The desired current output can be placed in the
Test Output (mA)
field, and this current
can then be output on the analog output by clicking on the
Output Test
button. If the current
displayed on the meter does not match the expected test output, the output may require
recalibration; repeat the procedure outlined above.
Once the analog output has been calibrated and tested, repeat the calibration and testing
procedure for all other analog outputs to be used. Once all analog outputs have been calibrated
and tested, be sure to save the calibration(s) to the analyzer by clicking on the
Temporary Write
/
Permanent Write
buttons.
4.5.1.2 Discrete Output Testing
At the bottom of the Output Test page is a row of circles associated with each of the discrete
outputs (relays and solenoids) on the analyzer’s IO board. The Discrete Output test section is
shown in Figure 50.
Figure 42: Discrete Output Testing
