Teledyne 4020 – Hydrocarbon analyzer (special version for automatic background gas switching) User Manual
Page 43
Total Hydrocarbon Analyzer
Installation
Teledyne
Analytical
Instruments
25
3.3.4 RS-232 Port
The digital signal output is a standard RS-232 serial communications
port used to connect the analyzer to a computer, terminal, or other digital
device. It requires a standard 9-pin D connector.
Output: The data output is status information, in digital form, updated
every two seconds. Status is reported in the following order:
1. The concentration in ppm
2. The range in use (R-1 = Range 1, R-2 = Range 2, R-3 =
Range 3, R-4 = Range 4)
3. The span of the range (0- 10.00 ppm, etc)
4. Mode the analyzer is in: ANLZ, ZERO, or SPAN
5. Which alarms—if any—are tripped (AL–1 and/or AL-2).
Each status output is followed by a carriage return and line feed. For
example:
5.88 ppm R-1 (0- 10.00 ppm) ANLZ AL-1
Input: The input functions using RS-232 that have been implemented
to date are described in Table 3-7.
Table 3-8: Commands via RS-232 Input
Command Description
as
Immediately starts an autospan.
az
Immediately starts an autozero.
Implementation: The RS-232 protocol allows some flexibility in its
implementation. Table 3-8 lists certain RS-232 values that are required
by the Model 4020 implementation.