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Campbell Scientific SC100 1-Channel Serial Data Interface User Manual

Page 4

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SC100 ISOLATED RS-232 BAUD RATE CONVERTER INTERFACE

2

Command to enter transparent mode:

ctrl-Q(17), I (73), S (83)

Command to exit transparent mode:

either
1) change the baud rate, parity status
2) change the initialize structure

Command for changing the baud rate,
parity, and error reporting:

ctrl-Q(17), I (73), B (66)

Following these three command bytes the
SC100 will expect:

Structure initialization information:

byte 1)

1 byte COMPUTER/SENSOR Baud

Rate:

16 - 38.4k baud
17 - 19.2k baud
18 - 9600 baud
19 - 4800 baud
20 - 2400 baud
21 - 1200 baud

Values other than these listed will result in non-
standard baud rates.

Buffering in one direction only (appropriate
delays should be programmed with baud rates
under 1200 baud when the datalogger transmits
character to the computer/sensors).

byte 2)

1 byte for parity (computer/sensor
side), full or half duplex (datalogger
side), error messages
(computer/sensor side).

Example

01010100 binary --> 54 hex -->84 decimal -->
send errors, even parity, full duplex

Bit6 (error/no error) - If set to 1 the SC100 will
report any framing, overrun, or parity errors
form the computer/sensor side. This
information will be added to the end of the
buffered data sent to the datalogger, and will
either be zero (0) for no errors, or one through
nine (1-9) for number of errors detected.

Bit4 (even/odd) - Even or odd parity if parity bit2
is set to one.

Bit3 (half/full) - There are two different versions
of Instruction 15 for the CR10 datalogger. Half
duplex, or full duplex. The PROM installed in
the CR10 determines the version. The CR10X
uses full duplex. Whenever the datalogger
executes Instruction 15, the DTR line goes high.
The DTR line remains high for transmitting and
goes low for receiving. With the full duplex
version, data can be received before the
transmitting has been completed (data can not
be received before the delay time entered in
parameter 3).

The SC100 will delay 12 msec before
transmitting the buffered data (parameter 3
must be 1 --> 10 msec).

Three out of the five different Input/Output
Configurations for Instruction 15 can be used
with the SC100 and they are 1, 2 and 4.

x

1=error

0=no error

x

1=even

0=odd

1=half

0= full

1=parity

0= none

x

x

bit7

bit6

bit5

bit4

bit3

bit2

bit1

bit0

x-don't care