Appendix B. Instruction 15: Control Port Serial I/O
B-5
B.2.3 Parameter 3 – CTS / Delay Before Send
If parameter 3 is zero (0), the CR10X 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
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.
B.2.4 Parameter 4 – First Control Port
Parameter 4 specifies the first control port for use by the first repetition. The first
control port is always the RTS/DTR line. More information on the control ports is
given in Section B.3, ‘Control Port Configuration and Sensor Wiring’.
B.2.5 Parameter 5 – Output Start Location
Parameter 5 specifies the first input location containing output, if any.
B.2.6 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 send nothing.
When sending a preamble or some command characters to a sensor, the characters
must be in the ASCII decimal equivalent code (see Appendix E). The preamble is
stored in sequential input locations with one ASCII decimal equivalent code
(0 to 127) in each location. The CR10X 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 150ms.
If the number of locations to send is followed by ‘--’, the CR10X 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 CR10X. Data points are
separated by a space, and the string is terminated with a Carriage Return and Line
Feed.
The data is transmitted with one start bit, eight data bits, no parity, and one stop
bit. For sensors requiring seven data bits with two stop bits, add 128 to the last
input location.
B.2.7 Parameter 7 – Input Termination Character
The termination character is used to mark the end of the ASCII string received by
the CR10X. Regardless of the configuration code, all eight 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.