3 Installation Model 3020T
3-10 Teledyne Analytical Instruments
• 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 3-4.
Table 3-4: Commands via RS-232 Input
Command Description
as<enter> Immediately starts an autospan.
az<enter> Immediately starts an autozero.
st<enter> Toggling input. Stops/Starts any status message output from
the RS-232, until st<enter> is sent again.
The RS-232 protocol allows some flexibility in its implementation.
Table 3-5 lists certain RS-232 values that are required by the 3020T imple-
mentation.
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 SEN-
SOR connector is not used, and the SOLENOID RETURN connectors are
used (without the –C option) to synchronize external gas control valves, if
desired. See Figure 3-7.