Vacon 100 INDUSTRIAL - 6. Communications; 6.1 Data Addresses in Modbus Messages; 6.2 Supported Modbus Functions

6
vacon • 30 Communications
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6. COMMUNICATIONS
Features of the Modbus-Vacon interface:
• Direct control of VACON
®
drive (e.g. Run, Stop, Direction, Speed reference, Fault reset)
• Full access to all VACON
®
parameters
• Monitor VACON
®
status (e.g. Output frequency, Output current, Fault code)
6.1 Data addresses in Modbus messages
All data addresses in Modbus messages are referenced to zero. The first occurrence of a data item
is addressed as item number zero. For example:
• The coil known as ‘Coil 1’ in a programmable controller is addressed as ‘Coil 0000’ in the
data address field of a Modbus message.
• Coil 127 decimal is addressed as ‘Coil 007E hex’ (126 decimal).
• Holding register 40001 is addressed as register 0000 in the data address field of the mes-
sage. The function code field already specifies a ‘holding register’ operation. Therefore the
‘4XXXX’ reference is implicit.
• Holding register 40108 is addressed as register 006B hex (107 decimal).
6.2 Supported Modbus Functions
The VACON
®
variables and fault codes as well as the parameters can be read and written from
Modbus. The parameter addresses are determined in the application. Every parameter and actual
value have been given an ID number in the application. The ID numbering of the parameter as well
as the parameter ranges and steps can be found in the application manual in question. The
parameter value must be given without decimals. If several parameters/actual values are read with
one message, the addresses of the parameters/actual values must be consecutive.
The address ranges of the different function codes are in many cases not relevant to the user and
can be ignored. The targeted information type (coil, register etc.) can be selected separate from the
address.
Table 15. Supported functions
Fun c tio n
(dec)
Function
(hex)
Modbus Function Name
TCP/
UDP
RTU Access type
Address
range (hex)
1 1 Read coils x Discrete (1-bit) 00000-0FFFF
2 2 Read Discrete Inputs x Discrete (1-bit) 10000-1FFFF
3 3 Read Holding Registers x x Register (16bit) 40000-4FFFF
4 4 Read Input Registers x x Register (16bit) 30000-3FFFF
5 5 Write Single Coils x Discrete (1-bit) 00000-0FFFF
6 6 Write Single Register x x Register (16bit) 40000-4FFFF
15 F Write Multiple Coils x Discrete (1-bit) 00000-0FFFF
16 10 Write Multiple Registers x x Register (16bit) 40000-4FFFF
23 17 Read/Write Multiple Registers x x Register (16bit) 40000-4FFFF
NOTE! Broadcasting not supported in TCP.
Broadcast supported with function code 06 and 16 in RTU and in UDP.