RS-485 Digital Communications
108
Modline 5
6.3
Sensor Rear Panel Setup for RS-485 Communication
The following Sensor RS-485 Communication attributes must be correctly selected at the Sensor Rear
Panel for communications to take place. RS-485 Commands for these functions are not provided. The
instructions are in manual Section 5
, page 82 for these functions.
6.3.1
CLCK – Communications Lock
Communications Lock provides for the configuration of the Modline 5 RS-485 Communications.
Communication can be configured to allow selection and adjustment of functions for Read and Write
(R / W) operation or Read Only (R / O) operation. Read Only operation causes write commands sent to
the Sensor to be turned into Read Commands.
R / O operation does allow the RS485 AC Automatic Calibrate Command to initiate a
CHK
and the PR Peak Picker Reset Command to perform a reset.
6.3.2
ADDR – Sets the Sensor Address
The Unit Address is a one digit number or single letter code. It ranges from a single numeric
0 to 9
to
and upper case A to Z. The Address factory default setting is 0 (zero).
6.3.3
BRAT – Baud Rate
The Sensor Baud Rate must match that of the other RS-485 device. Four baud rates are supported: 9600,
19200, 38400, and 57600 bits of information per second.
6.4
Communication Protocol
Communication is half-duplex, two wire. The Sensor does not support simultaneous
transmit and
receive. Four baud rates are supported: 9600, 19200, 38400, and 57600 bits of information per second.
All characters are ASCII 7 bits, even parity, 1 stop. Commands have a response. Another command
should not be sent until a response has been completely received. There is a 1-millisecond minimum
delay between receipt of command and response. The maximum delay is less than 200 milliseconds.
6.4.1
Command Message Format
All command messages have the same format:
<Start Bit> <Sensor Address> <Channel Number> <Command Code> [<Value>] <Carriage Return>
Example: #A0CCXXXXX<CR> Where:
Start Bit = #
Always the pound sign character.
Sensor Address = A
A single alphanumeric character address of the Sensor, 0 to 9, A to Z
0 (zero) is the factory-default setting. The wild card address of ‘ ? ‘ is accepted
by the MODLINE 5 regardless of its set address. Do not use the “?” address
if more than one Sensor is connected.
Channel Number = 0
Is always the 0 (zero) character.
This one-digit entry value is not used in the MODLINE 5. SET to 0 (zero) for
future use.
