Teledyne 7300a - NDIR analyzer - Manual (Page 17)

Infrared Gas Analyzer Installation 2
2-5 Teledyne Analytical Instruments
4–20 mA dc % Range: Current rises linearly with concentration, from 4
mA at 0 concentration to 20 mA at full scale. (Full
scale = 100% of programmable range.)
4–20 mA dc Range ID: 8 mA = Range 1, 12 mA = Range 2, 16 mA =
Range 3, 20 mA = Range 4.
Table 2-2: Analog Output Connections
Pin Function
3 + Range ID, 4-20 mA, floating
4 – Range ID, 4-20 mA, floating
5 + % Range, 4-20 mA, floating
6 – % Range, 4-20 mA, floating
8 + Range ID, 0-1 V dc
23 – Range ID, 0-1 V dc, negative ground
24 + % Range, 0-1 V dc
7 – % Range, 0-1 V dc, negative ground
Examples:
The analog output signal has a voltage which depends on gas concen-
tration relative to the full scale of the range. To relate the signal output to the
actual concentration, it is necessary to know what range the instrument is
currently on, especially when the analyzer is in the autoranging mode.
The signal output for concentration is linear over the currently selected
analysis range. For example, if the analyzer is set on a range that was defined
as 0–10 % carbon monoxide, then the output would be as shown in
Table 2-3.
Table 2-3: Analog Concentration Output—Example
Percent Voltage Signal Current Signal
CO Output (V dc) Output (mA dc)
0 0.0 4.0
1 0.1 5.6
2 0.2 7.2
3 0.3 8.8
4 0.4 10.4
5 0.5 12.0