Campbell CR23X, Operator'S Manual

Page: 248 / 374

APPENDIX B. CONTROL PORT SERIAL I/O INSTRUCTION 15
B-4
PARAMETER 3 - CTS / DELAY BEFORE SEND
(applies to control port configuration only)
If Parameter 3 is zero (0), the CR23X waits for
the Clear To Send to come high before sending
output. If Clear To Send does not come high
within the time specified in Parameter 9, output
does not occur and -99999 is placed in the Input
Memory Location specified in Parameter 10.
If Parameter 3 is non-zero, this parameter
specifies the length of a delay in units of 0.01
seconds between asserting Request To Send
and sending output. A CTS line is not used.
PARAMETER 4 - CONTROL PORT
CONFIGURATION
A two-digit parameter (AB) indicates the control
port(s) that will be used by the first repetition
(A+1 and/or B+1 may also be used depending
on the P15 CONFIGURATION selected).
Control Ports 1, 2, 3, and 4 support hardware
flow control (DTR/RTS and CTS lines). Control
ports 5, 6, 7, and 8 support transmit and receive
(TXD and RXD) data lines.
A is the control port used for DTR/CTS:
0 Don't use DTR/RTS and CTS
1 Control Port 1
2 Control Port 2
3 Control Port 3
4 Control Port 4
B is the control port used for TXD/RXD:
5 Control Port 5
6 Control Port 6
7 Control Port 7
8 Control Port 8
9 CR23X RS-232 Port
Example: An entry of 15 specifies Port 1 for
DTR and Port 5 for either RXD using
CONFIGURATION 1.
More information on control ports is given in
Section B4, “Control Port Configuration and
Sensor Wiring.”
PARAMETER 5 - OUTPUT START LOCATION
Parameter 5 specifies the first input location
containing data to be sent, if any.
PARAMETER 6 - NUMBER OF LOCATIONS TO
SEND; PREAMBLE OR DATA
Parameter 6 specifies the number of input
locations to send. A "--" following the number
indicates that the datalogger needs to convert
the values to ASCII. Entering only the number
of input locations (i.e., no "--") implies that the
values are in ASCII decimal equivalent code.
A "0" in Parameter 6 means to send nothing.
If outputting a preamble or command
characters to a sensor, the characters must be
in the ASCII decimal equivalent code (Appendix
E). The preamble is stored in sequential input
locations with one ASCII decimal equivalent
code (0 to 127) in each location. The CR23X
sends the preamble one ASCII character per
input location. The decimal codes may be
loaded into input locations using Instruction 30.
Any negative value indicates that a "BREAK"
should be sent. A "BREAK" is a spacing
condition of more than 150 milliseconds.
If the number of locations to send is followed by
"--", the CR23X sends an ASCII representation
of the value in the input location. Seven ASCII
characters are sent for each input location
(+ or -, five digits, and a decimal point). This
feature is used most often when outputting data
to another CR23X. Data points are separated
by a space, and the string is terminated with a
Carriage Return and Line Feed.
The data are transmitted with 1 start bit, 8 data
bits, no parity, and one stop bit. For sensors
requiring 7 data bits with 2 stop bits, add 128 to
the last input location.
PARAMETER 7 - INPUT TERMINATION
CHARACTER
The termination character is used to mark the
end of the ASCII string received by the CR23X.
Regardless of the configuration code, all 8 bits
are used in determining the termination
character. Thus, if the sensor is sending parity,
it may be necessary to add 128 to the decimal
value of the character.
If the termination character IS NOT
encountered, input will continue until time out
(Parameter 9) or until the maximum number of
characters (Parameter 8) is received.