Metex 2200P pH Analyzer/Controller User Manual
Page 28
Model 2200P
Page 26
7.6 Adjust 0-1 mA / 0-5 Vdc Output
7.6.1
It may be desirable to fine tune the 0-1 mA / 0-5 Vdc output to take into account the
characteristics of your particular loop. The following method involves a high and
low calibration and requires the use of a digital multi-meter. (DMM). Proceed as
follows ignoring the instrument display:
a) Turn off the power to the instrument. Connect your DMM in parallel with the 0-5
Vdc output terminals on the power supply board.
b) Turn on the power. Enter the Utility Menu as described in 7.2.1.
c) Press MENU until the RELAY A RELAY ON LED illuminates, which is "0-1 mA/
0-5 Vdc output adjust, low" in the Utility Menu (See table in 7.2.2). Use the
arrow keys to make your DMM read 1.25V. Press ENTER twice to confirm.
d) Press MENU and the RELAY A RELAY OFF LED will illuminate, which is "0-1
mA / 0-5 Vdc Output adjust, high" in the Utility Menu (See table in 7.2.2.) Use
the arrow keys to make your DMM read 3.75V. Press ENTER twice to confirm.
e) Press RUN to return to on line or press MENU to proceed to another item in the
Utility Menu.
7.7 Adjust 4-20 mA Output
7.7.1
It may be desirable to fine tune the 4-20 mA isolated output to take into account the
characteristics of your particular loop. Before deciding that the adjustment is
necessary, be aware of the "Output High" and "Output Low" settings you may have
programmed as described in Section 5.4. The following method involves a high and
low calibration and requires the use of a Digital Multi-meter (DMM). Proceed as
follows ignoring the instrument display.
a)
Turn off the power to the instrument. Connect your DMM in series with the 4-20
mA output terminals on the power supply board.
b) Turn on the power. Enter the Utility Menu as described in 7.2.1.
c) Press MENU until the ALARM HIGH LED illuminates, which is "4-20 mA Output
adjust, low" in the Utility Menu (See table in 7.2.2.) Now use the arrow keys to
make your DMM read 8 mA. Press ENTER twice to confirm.
d)
Press MENU and the ALARM LOW LED illuminates, which is "4-20 mA Output
adjust, high" in the Utility Menu (See table in 7.2.2). Now use the arrow keys to
make your DMM read 16 mA. Press ENTER twice to confirm.
e)
Press RUN to return to on line or press MENU to proceed to another item in the
Utility Menu.