Ametek OXYvisor - A7.2 - Configuration; Figure A.34 - Modbus Connection

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Installation, Operation & Maintenance Manual
OXYvisor Optical Oxygen Analyzer
The following setting are used to communicate with the OXYvisor as a Slave Device.
The OXYvisor Modbus RTU protocol uses a subset of the standard Modbus RTU function codes to provide
access to process-related information. Several standard function codes are employed and supported, shown
in the table below. These standard function codes provide basic support for IEEE 32-bit oating point numbers
and 16-bit integer register representation of instrument’s process data.
A7.2 - Conguraon
A7.2.1 - Sengs
A7.2.2 - Funcon Codes
Terminal
Terminal
RS-485 Master
Data (B) -
Data (A) +
< 4000 ft (1220 meters)
The maximum distance of RS-485 without using a repeater is
4000 feet (1220 meters) at baud rates up to 90Kbps. Extend that
distance by adding an RS-485 Repeater or Optically Isolated
Repeater every 4000 feet.
USEFUL INFORMATION
Setting Value
Mode RTU
Baud rate 115200
Data Bits 8
Stop Bits 2
Parity None
High Byte First

Slave ID 01, 02, …
Function
Code
Name Usage
03 Read Holding Registers Read Data in 16-bit Register Format (high/low). Used to read integer or oating-point process
data. Registers are consecutive and are imaged from the instrument to the host.
04 Read Input Registers
06 Write Single Register Write Data in 16-bit Integer Format (high/low) ONLY.
16 Write Multiple Registers Write Data in 16-bit Format (high/low). Used to write integer and oating-point override data.
Registers are consecutive and are imaged from the host to the instrument.
Note: Can write oating point data using this Function Code
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Figure A.34 - Modbus Connection