MAGS1 User Guide
11
V1.5 22-1-2016
4.2. Introduction
This section describes the MAGS1 Modbus RTU communication protocol.
4.3. Definitions and Abbreviations
CRC
Cyclic Redundancy Check, Used for error-checking in Modbus
RTU. See appendix
Modbus master
A Modbus device, which is able to access data in one or more
connected Modbus slaves
Modbus slave
A Modbus device, which is able to respond to requests from a
single Modbus master
Modbus address
Throughout this document the following notation is used to
address Modbus RTU registers:
1234 - Holding register 1234 (addressed in messages by 1233)
RS485
Refers to the communication standard TIA/EIA-485 or RS-485
RTU
Remote Terminal Unit - Standard Modbus transmission mode
4.4. References
Reference 1
Modbus over Serial Line Specification & Implementation guide
v. 1.0 modbus.org 12/02/02
Reference 2
Modbus Application Protocol Specification v. 1.1 modbus.org
12/06/02
4.5. Technical data
ARKON Flowmeter Modbus RTU specification
Device type
Slave
Baud rates
9600, 14400, 19200, 38400, 57600, 115200 bits/sec.
Number of stations Recommended:
max. 31 per segment without repeaters
Device address range
1-247
Protocol
Modbus RTU (Other Modbus protocols like ASCII, Plus or
TCP/IP are not supported)
Electrical interface
RS485
Supported function code
3 read holding registers
16 write multiple registers
Broadcast
No
Maximum cable length
RS485 Specification limits
Standard Modbus over serial line v1.0
Certified
No
