Danfoss VLT Compressor Drive CDS 803 - Page 5

7.4.1 Content of a Character (byte) 52
7.4.2 Telegram Structure 52
7.4.3 Telegram Length (LGE) 52
7.4.4 Frequency Converter Address (ADR) 52
7.4.5 Data Control Byte (BCC) 52
7.4.6 The Data Field 53
7.4.7 The PKE Field 54
7.4.8 Parameter Number (PNU) 54
7.4.9 Index (IND) 54
7.4.10 Parameter Value (PWE) 54
7.4.11 Data Types Supported by the Frequency Converter 55
7.4.12 Conversion 55
7.4.13 Process Words (PCD) 55
7.5 Examples
55
7.6 Modbus RTU Overview
56
7.6.1 Prerequisite Knowledge 56
7.6.2 What the User Should Already Know 56
7.6.3 Overview 56
7.6.4 Frequency Converter with Modbus RTU 57
7.7 Network Conguration
57
7.8 Modbus RTU Message Framing Structure
57
7.8.1 Introduction 57
7.8.2 Modbus RTU Telegram Structure 57
7.8.3 Start/Stop Field 58
7.8.4 Address Field 58
7.8.5 Function Field 58
7.8.6 Data Field 58
7.8.7 CRC Check Field 58
7.8.8 Coil Register Addressing 58
7.8.9 How to Control the Frequency Converter 60
7.8.10 Function Codes Supported by Modbus RTU 60
7.8.11 Modbus Exception Codes 61
7.9 How to Access Parameters
61
7.9.1 Parameter Handling 61
7.9.2 Storage of Data 61
7.10 Examples
62
7.10.1 Read Coil Status (01 hex) 62
7.10.2 Force/Write Single Coil (05 hex) 62
7.10.3 Force/Write Multiple Coils (0F hex) 63
7.10.4 Read Holding Registers (03 hex) 63
Contents Design Guide
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