Teledyne 3000TA Operating Instructions Manual page 30

3 Installation
Note: The Remote Probe connector (paragraph 3.3.3) provides
signals to ensure that the zero and span gas valves will be
controlled synchronously. If you have the –C Internal valve
option—which includes additional zero and span gas inputs—
the 3000T automatically regulates the zero, span and sample
gas flow.
Range ID Relays: Four dedicated Range ID relay contacts. The first
three ranges are assigned to relays in ascending order—Low range is as-
signed to Range 1 ID, Medium range is assigned to Range 2 ID, and High
range is assigned to Range 3 ID. The fourth range is reserved for the Air Cal
Range (25%).
Network I/O: A serial digital input/output for local network protocol.
At this printing, this port is not yet functional. It is to be used in future
options to the instrument.
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.
The 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 3-1.
Table 3-1: 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 3-2 lists certain RS-232 values that are required by the 3000TA
implementation.
3-8 Teledyne Analytical Instruments
Model 3000TA