D-Guard
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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
Bottom left ('next') soft-key moves to the next screen
From the zero calibration page, operate the 'Span Cal' soft-key
to move on to the next screen (span calibration page).
The second screen is span calibration .
Operate the 'DRT' soft-key to move to the next screen (DRT).
Bottom left ('next') soft-key moves to the next screen
12.5.1
Setting the 4mA Output Current
The third screen is the DRT function screen.
Operate the 'SET 4mA' soft-key to move to the 4mA
calibration screen.
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
From the 4mA calibration screen
12.5.2
Setting the 20mA output Current
From the 4mA calibration screen, operate the 'SET 20mA' soft-
key to move to the 20mA calibration screen.
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