Teledyne 3000ZA-3X - Trace oxygen analyzer - Manual (Page 47)

Trace Oxygen Analyzer Operation
Teledyne Analytical Instruments 35
4-20mA Gain: 0
4-20mA Limit: FALSE
Track in Cal:
Yes
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4-20mA Offset: Pressing ENTER causes the number after 'Offset:'
to start flashing. Then pressing UP or DOWN selects a number ranging
from –341 to 500. The analog output may be sampled using a DMM at
this time. When the parameter is zero, the analog voltage output should
be very close to 0.0 (4.00 madc if the 4-20 madc is being adjusted).
Adjusting the parameter up or down causes the analog output to go up or
down respectively. When in Analyze mode, this offset value is added to
the analog output as determined by percentage of range. Note that due to
difference in electronic offsets between both analog outputs, the 0-1 vdc
and the 4-20 madc, only one may be adjusted. In other words adjusting
the 0-1 vdc output to have 0.00 vdc output may lead the 4-20 madc
output to have an offset.
4-20mA Gain: Pressing ENTER causes the number after 'Offset:'
to start flashing. Then pressing UP or DOWN selects a number ranging
from –500 to 500. The analog output may be sampled using a DMM at
this time. When the parameter is zero, the analog output should be very
close to 1.00 vdc or 20.0mA plus the offset caused by the Offset
parameter (above). Adjusting the parameter up or down causes the
analog output to go up or down respectively. When in Analyze mode,
this gain value is factored with the analog output as determined by
percentage of range .
The Offset and Gain parameters are unitless numbers. Their effect
is determined empirically using a DMM. They affect the analog output
according to the following formula:
Output = ([% of Range] * GAIN) + OFFSET
4-20mA Limit: Pressing ENTER causes TRUE/FALSE to start
flashing. Then pressing UP or DOWN toggles the value. When TRUE,
the analog output cannot put less than 4mA out of the analog output
(during ANALYZE MODE). When FALSE, the output may be lower than
4mA by approximately 10%.