Specifications

7.4.5 Data Control Byte (BCC) 82
7.4.6 The Data Field 83
7.4.7 The PKE Field 84
7.4.8 Parameter Number (PNU) 84
7.4.9 Index (IND) 84
7.4.10 Parameter Value (PWE) 84
7.4.11 Data Types Supported by the Frequency Converter 85
7.4.12 Conversion 85
7.4.13 Process Words (PCD) 85
7.5 Examples
85
7.6 Modbus RTU Overview
86
7.6.1 Assumptions 86
7.6.2 What the User Should Already Know 86
7.6.3 Modbus RTU Overview 86
7.6.4 Frequency Converter with Modbus RTU 87
7.7 Network Configuration
87
7.8 Modbus RTU Message Framing Structure
87
7.8.1 Frequency Converter with Modbus RTU 87
7.8.2 Modbus RTU Message Structure 87
7.8.3 Start/Stop Field 88
7.8.4 Address Field 88
7.8.5 Function Field 88
7.8.6 Data Field 88
7.8.7 CRC Check Field 88
7.8.8 Coil Register Addressing 88
7.8.9 How to Control the Frequency Converter 90
7.8.10 Function Codes Supported by Modbus RTU 90
7.8.11 Modbus Exception Codes 91
7.9 How to Access Parameters
91
7.9.1 Parameter Handling 91
7.9.2 Storage of Data 91
7.9.3 IND 91
7.9.4 Text Blocks 91
7.9.5 Conversion Factor 91
7.9.6 Parameter Values 91
7.10 Examples
92
7.10.1 Read Coil Status (01 HEX) 92
7.10.2 Force/Write Single Coil (05 HEX) 92
7.10.3 Force/Write Multiple Coils (0F HEX) 93
7.10.4 Read Holding Registers (03 HEX) 93
Contents
VLT
®
HVAC Basic Drive FC 101 Design Guide
MG18C502 - Rev. 2013-09-06 3