Trace Oxygen Analyzer Installation 3
3-9
Teledyne Analytical Instruments
The voltage from these outputs is nominally 0 V for the OFF and
15 V dc for the ON conditions. The maximum combined current that can be
pulled from these output lines is 100 mA. (If two lines are ON at the same
time, each must be limited to 50 mA, etc.) If more current and/or a different
voltage is required, use a relay, power amplifier, or other matching circuitry
to provide the actual driving current.
In addition, each individual line has a series FET with a nominal ON
resistance of 5 ohms (9 ohms worst case). This can limit the obtainable
voltage, depending on the load impedance applied. See Figure 3-6
.
Figure 3-6: FET Series Resistance
3.3.2.3 RS-232 Port
The digital signal output is a standard, full duplex RS-232 serial com-
munications port used to connect the analyzer to a computer, terminal, or
other digital device. It requires a standard 9-pin D connector.
The output data is status information, in digital form, updated every two
seconds. Status is reported in the following order:
• The concentration in ppm or percent
• The range in use (HI, MED, LO)
• The span of the range (0-100 ppm, etc)
• Which alarms—if any—are disabled (AL–x DISABLED)
• Which alarms—if any—are tripped (AL–x ON).
Each status output is followed by a carriage return and line feed.
Three input functions using RS-232 have been implemented to date.
They are described in Table 3-5.