Trace Oxygen Analyzer
Installation
Teledyne
Analytical
Instruments
29
The RS-232 protocol allows some flexibility in its implementation.
Table 3-5 lists certain RS-232 values that are required by the 3020T
implementation.
Table 3-5: Required RS-232 Options
Parameter
Setting
Baud
2400
Byte
8
bits
Parity
none
Stop
Bits
1
Message
Interval
2
seconds
3.3.9 Remote Sensor and Solenoid Valves
The 3020T is a single-chassis instrument, which has its own sensor
and, in the –C option, its own gas-control solenoid valves. The
REMOTE SENSOR connector is not used, and the SOLENOID
RETURN connectors are used (without the –C option) to synchronize
external gas control valves. See Figure 3-7.
Figure 3-7: Remote Solenoid Return Connector Pinouts
The voltage from these outputs is nominally 0 V for the OFF and
15 VDC 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 could limit the