UMC Modbus 通讯连接.docVIP

Introduction The Universal Motor Controller UMC22 can be connected to different field busses via FieldbusPlugs. So far FieldbusPlugs are available for PROFIBUS DP-V0/V1, DeviceNet, MODBUS RTU and AS-iinterface. This document is a tutorial on how data provided by the UMC is mapped to Modbus RTU. UMC22 telegram contents are taken from [1] that describes UMC22 Version 3.1. This tutorial is also usable for later software versions of UMC22. Only the meaning of single bits may change because of new UMC22 features. References: [1] UMC22-FBP Technical Description, 2CDC 135001 D0205 [2] MODBUS FBP Technical Description, 2CDC 194001 D0202 Connecting UMC22 to MODBUS RTU MODBUS is an application layer messaging protocol, positioned at level 7 of the OSI model that provides client/server communication between devices connected on different types of buses or networks. The MODBUS application data unit is built by the client that initiates a MODBUS transaction. The function indicates to the server what kind of action to perform. The MODBUS application protocol establishes the format of a request initiated by a client. For connecting the UMC to MODBUS networks with RS485 as physical layers the FieldbusPlug MRP21 must be used. For technical details about MRP21 please see [2]. The following figure shows the principle setup between a Modbus master and a connected UMC. Before any communication can take place the right baud rate must be selected. Depending of the UMC address a specific baud rate is used from the MRP21. For details see [2] page 23. In the following sections example telegrams are shown. The content may vary depending on the chosen control function of the UMC and the UMC version itself! Start Configuration With the new firmware version (indicated with an index e or higher) also the parameterization telegram has become optional. This means that both configuration and parameterization telegrams are optional now. Step 1a (optional): After power-up of UMC