Appendix B. Serial Port Data Transfer Modes

This appendix describes the serial port set-up in some detail. Please note that the numerical option codes vary between the command line set-up and the datalogger command set-up. The ones listed below are those for the command line mode.

B.1 Baud rates

The SDM-SIO4 ports can support 16 baud rates if set up from the command line but only 9 are available from datalogger set-up using SDM commands. An asterisk indicates not available in SDM command mode:-

0.57600 baud *

1.115200 baud *

2.25 baud *

3.50 baud *

4.75 baud *

5.110 baud *

6.150 baud *

7.300 baud

8.600 baud

9.1200 baud

10.2400 baud

11.4800 baud

12.9600 baud

13.19200 baud

14.38400 baud

15.76800 baud

NOTE If the baud rate is higher than 9600 on two or more ports the SDM-SIO4 may not be able to reliably collect data when there is a lot of simultaneous input activity of more than 16 bytes without delays. This limitation can normally be overcome by careful planning of when data is requested from the RS232 devices, by keeping data to less than 16-byte blocks at full speed, or by using delays between characters. Please contact Campbell Scientific for further advice.

B.2 Stop Bits

The number of stop bits can be set to 1, 1.5 and 2.

0.1 stop bit

1.1.5 stop bits if 5-bit data length or 2 stop bits for all other data lengths.

B.3 Data Length

The data length can be set from 5 to 8 bits.

0.5 data bits

1.6 data bits

2.7 data bits

3.8 data bits

B-1

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Campbell Hausfeld SDM-SIO4 manual Appendix B. Serial Port Data Transfer Modes, Baud rates, Stop Bits, Data Length