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
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 data logger to the sensor)
Receive buffer size:
6143 bytes (buffer from the sensor to the data logger)
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 data
logger requests data from the SDM-SIO1A.
SDM-SIO1A and SDM-SIO4A Serial Input/Output Modules
4
