SDM-SIO1A and SDM-SIO4A Serial Input/Output Modules
4
5. Specifications
5.1 Supported Data Rates and Protocols
Data rates and protocols are set up using the
SerialOpen()
instruction in
CRBasic. The
SerialOpen()
instruction is discussed in Section
(p. 16)
.
Supported data rates:
300, 1200, 2400, 4800, 9600, 19200, 38400,
57600, and 115200 bits/s
Supported modes of operation:
RS-232 (full duplex and receive only)
RS-485 (half and full duplex)
RS-422 (full duplex)
Hardware CTS/RTS flow control is
supported in RS-232 mode. The handshaking
lines can also be used as general purpose I/O
lines.
Supported data formats:
8, 7-bit data size*; none, odd or even parity;
one or two stops bits
* In 7-bit mode with no parity, the user must
ensure that the characters received by the
SDM-SIO1A have a delay of at least one bit
period between them. This does not affect
any other configuration and does not affect
transmissions out of the SDM-SIO1A.
Miscellaneous information:
The SDM-SIO1A does not support auto baud
rate detection or use of the serial port for
general PakBus® communications. Modbus
and DNP3 communications are supported.
Buffer sizes
Transmit buffer size:
767 bytes (buffer from the datalogger to the
sensor)
Receive buffer size:
6143 bytes (buffer from the sensor to the
datalogger)
Both transmit and receive buffers are fill and
discard type; that is, once the buffers become
full, no new information is accepted and all
further data is discarded until space is made
when the datalogger requests data from the
SDM-SIO1A.