Current Loop Output Calibration; Setting The 4Ma Output Current; Setting The 20Ma Output Current - GasTech D-Guard2S Operator's Manual

12.5. Current Loop Output Calibration

The current loop output signal is not expected to require re-adjustment under normal operating conditions..
If however setting is required, the following procedure describes the process.
After entering the calibration system
From the zero calibration page, operate the 'Span Cal' soft-key
to move on to the next screen (span calibration page).
Bottom left ('next') soft-key moves to the next screen
The third screen is the DRT function screen.
Operate the 'SET 4mA' soft-key to move to the 4mA
calibration screen.
From the 4mA calibration screen
From the 4mA calibration screen, operate the 'SET 20mA' soft-
key to move to the 20mA calibration screen.
Bottom left ('next') soft-key moves to the next screen
The second screen is span calibration .
Operate the 'DRT' soft-key to move to the next screen (DRT).
12.5.1

Setting the 4mA Output Current

To adjust the 4mA output signal, place a digital multi-meter on
the 'Loop' test point pins on the main system board.
Operate the up or down soft-keys to adjust the current loop
output value. The setting will be fairly sensitive if the current
loop value is close the ideal value. Short 'dabs' of the up and
down keys should be sufficient to bring the value back into the
correct range. Each time a change is made, the 'home' icon'
will change to the 'save' icon. One a value is saved, the icon
will revert to the 'home' icon. Further changes will again show
the 'save' icon. The final value must be 4.00mA ± 0.01mA
12.5.2

Setting the 20mA output Current

To adjust the 20mA output signal, place a digital multi-meter
on the 'Loop' test point pins on the main system board.
Operate the up or down soft-keys to adjust the current loop
output value. The setting will be fairly sensitive if the current
loop value is close the ideal value. Short 'dabs' of the up and
down keys should be sufficient to bring the value back into the
correct range. Each time a change is made, the 'home' icon'
will change to the 'save' icon. One a value is saved, the icon
will revert to the 'home' icon. Further changes will again show
the 'save' icon. The final value must be 20.00mA ± 0.01mA
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D-Guard