
Installation Model
3020T
Teledyne
Analytical
Instruments
28
Table 3-3: RS-232 Signals
RS-232 Sig
RS-232 Pin
Purpose
DCD 1 Data
Carrier
Detect
RD 2 Received
Data
TD 3 Transmitted
Data
DTR 4 Data
Terminal
Ready
COM 5 Common
DSR 6 Data
Set
Ready
RTS 7 Request
to
Send
CTS 8 Clear
to
Send
RI 9 Ring
Indicator
The data sent is status information, in digital form, updated every
two seconds. Status is reported in the following order:
The concentration in percent
The range in use (HI, MED, LO)
The span of the range (0-100 %, 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.
Four 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.
co
<enter>
Reports “Raw Cell Output” (current output of the
sensor itself) in
A. For example—
Raw Cell Output: 99
A
st
<enter>
Toggling input. Stops/Starts any status message output
from the RS-232, until
st
<enter> is sent again.