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Operating Instructions
6.7.3.6. Current Loop Output Span and Offset Adjustment
A Current Loop Option may be purchased for the A1 and A2 Analog outputs of the
analyzer. This option places circuitry in series with the output of the D-to A
converter on the Mother Board that changes the normal DC voltage output to a 0 -
20 milliamp signal. The outputs can be ordered scaled to any set of limits within
that 0-20 mA range, however most current loop applications call for either 0-20 mA
or 4-20mA range spans. All current loop outputs have a + 5% over range. Ranges
whose lower limit is set above 1 mA also have a –5 under range.
To switch an Analog Output from voltage to current loop, follow the instructions in
Section 6.7.3.2 and select CURR from the list of options on the "Output Range"
menu.
Adjusting the signal zero and span levels of the current loop output is done by
raising or lowering the voltage output of the D-to-A converter circuitry on the
analyzer's Mother Board. This raises or lowers the signal level produced by the
Current Loop Option circuitry.
The software allows this adjustment to be made in 100, 10 or 1 count increments.
Since the exact amount by which the current signal is changed per D-to-A count
varies from Output-to-Output and instrument–to–instrument, you will need to
measure the change in the signal levels with a separate, current meter placed in
series with the output circuit.
Figure 6-3: Setup for Checking Current Output Signal Levels
106
See Table 5 –8 for
pin assignments on
the for ANALOG
connector located on
the instruments rear
panel
I OUT +
I OUT -
MODEL
300E
Do not exceed 60 V peak voltage between current loop outputs
and instrument ground.
mADC
IN
OUT
I IN +
I IN -
Recordeing
Device
CAUTION
Model 400E Ozone Analyzer
Instruction Manual
P/N 04316 Rev: B
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