AR100 Operation Manual
© 2018 Schmitt Industries
Revision 1.1
13
The parameters are stored in nonvolatile memory of the sensor. Correct
changing of the parameters is carried out by using the parameterization program
supplied with the sensor or a user program.
Description of RS232 and RS485 interfaces
Data exchange with the sensor is carried out over the Acuity or Modbus RTU
protocols in binary format or in the ASCII format. The protocol and the data
format are selected using the parameterization program.
RS232 port
The RS232 port ensures a “point-to-point” connection and allows the sensor to
be connected directly to RS232 port of a computer or controller.
RS485 port
In accordance with the protocol accepted and hardware capability, the RS485
port makes it possible to connect up to 127 sensors to one data collection unit by
a common bus circuit.
Serial data transmission format
Data message has the following format:
1 start-bit
8 data bits
1 even bit
1 stop-bit
Modes of data transfer
Through these serial interfaces the measurement data can be obtained by two
methods:
•
by single requests (inquiries);
•
by automatic data streaming (stream).
Communication sessions types
The communications protocol is formed by communication sessions, which are
only initiated by the ‘master’ (PC, controller). There are two kinds of sessions
with such structures:
1) “request”, [“message”] — [“answer”],
square brackets include optional
elements.
2) “request” — “data stream” — [“request”].
