The EDIT-CHANNELS-DETAilS
Screen
(continued)
Unretained Solute Time
If resolution has been selected to
be printed in the chromatogram report,
then a Unretained Solute Time value
needs to be entered to ensure correct
resolution calculations. Enter the num–
ber of minutes an
Unretained
Solute
takes to pass through the column. This
value is used in the determination of
peak resolutionstatistics.
Control
By
... ... ..... ......
-
fOURCHANNEL
MODEL
202AID BOARD
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.
,
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S""CU
CHANNEl.
MODEL 20) AIDBOARD
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-
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:.- .!
:7 :-.
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'1"!.
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.
The AID Board that is built into the SRI gas chromatograph includes two digital-to–
analog converters or DACs. DAG1 is primarily used to control the column oven #1
temperature ramp
by
introducing 10mV
I
°C to the oven heating circuit and is pro–
grammable by editing the Channel 1- Temperature control window. DAC2 is primarily
used to control the column oven #2 temperature ramp. Carrier gas E.P.C. pressure is
also programmable by editing the Channel 2-TemperaturefPressure control window.
The DACs may be used to control Pressure by following the procedure described be–
low and then selecting Pressure in the Control By window of the Edit-Channels–
Details screen.
To avoid startup difficulties, the
Carrier E.P.C. is shipped disabled. To
enable the use of the DACs to set up a
Pressure Program, only a single wire
needs to be moved inside the G.C..
Unplug the G.G. and remove the six
screws which secure the bottom cover.
Tilt the G.C. onto its back and remove
the bottom cover. The AID Board is
green in color and is mounted on the
right-hand side of the G.C. chassis.
Locate the Green wire with a White
stripe on the AID Board. This is the
Carrier Program wire. Normally thiswire is connected to a ground (GO) screw termi–
naL Unscrew the Carrier Program wire and connect
it
to the temperature/pressure #2
(TP2) screw terminal also on the AID Board. Re-attach the bottom cover, connect
power and re-establish communication between the G.G. and the computer. Select
Pressure in the Control By windowof the Edit-Channels-Channel 2-Details screen.
A pressure program ramp set up inChannel 2
will
now control the Carrier Gas E.P.C.
pressure by introducing 10mV for every P.S.!.. Turn the Carrier 1 Local Setpoint to
zero. This is necessary since the Local setpoint is added to the programmed E.P.C.
input indetermining the Carrier 1 totalsetpoint.
