Specifications

Register Number Description
00001-00006 Reserved
00007 Last error code from an FC data object interface
00008 Reserved
00009 Parameter index*
00010-00990 000 parameter group (parameters 001 through 099)
01000-01990 100 parameter group (parameters 100 through 199)
02000-02990 200 parameter group (parameters 200 through 299)
03000-03990 300 parameter group (parameters 300 through 399)
04000-04990 400 parameter group (parameters 400 through 499)
... ...
49000-49990 4900 parameter group (parameters 4900 through 4999)
50000 Input data: frequency converter control word register (CTW).
50010 Input data: Bus reference register (REF).
... ...
50200 Output data: frequency converter status word register (STW).
50210 Output data: frequency converter main actual value register (MAV).
Table 7.18 Holding Registers
* Used to specify the index number to be used when accessing an indexed parameter.
7.8.9 How to Control the Frequency Converter
This section describes codes that can be used in the function and data fields of a Modbus RTU message.
7.8.10 Function Codes Supported by Modbus RTU
Modbus RTU supports use of the following function codes in the function field of a message.
Function Function Code
Read coils 1 hex
Read holding registers 3 hex
Write single coil 5 hex
Write single register 6 hex
Write multiple coils F hex
Write multiple registers 10 hex
Get comm. event counter B hex
Report slave ID 11 hex
Table 7.19 Function Codes
Function Function
Code
Sub-
function
code
Sub-function
Diagnostics 8 1 Restart communication
2 Return diagnostic register
10 Clear counters and
diagnostic register
11 Return bus message count
12 Return bus communi-
cation error count
13 Return bus exception error
count
14 Return slave message
count
Table 7.20 Sub-function Codes
Installation and Set-up VLT® HVAC Drive FC 102 Design Guide
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