For example, if your user manual recommends that you use address 40001 to communicate with a register, you can use 400001 to communicate with it in LabVIEW DSC or on a Modbus I / O server. To configure the Modbus communication you need to know at least the basic information about Modbus protocol.
This is a powerful feature and with this post i explain how to enable and how to use it. The latest PLC Allen Bradley Micrologix 1400 is provided with Modbus TCP and RTU. At this time, it is possible to add 0 between the first and second bits so that the 5-bit address becomes 6 bits. Modbus configuration example for an Allen Bradley Micrologix 1400. Unsupported IVI and LabVIEW Plug and Play drivers for some legacy. The following is an example of a Modbus RTU request for obtaining the AI value of the holding registers from registers 40108 to 40110 with the address of the device 17. Each table has its own offset, respectively: 1, 10001, 3001. Sometimes, the last 4 bits of the Modbus address are marked as offset. Sample code using our chamber controller interface command set is provided below. The difference between these two quantities is offset. Because the data type is already included in the function code, the Modbus address of Siemens i0.0 is actually 000000, and the Modbus address of i2.0 is 000016 (or hexadecimal number 16 # 0010), not 010017. For example, the Modbus address of i0.0 is 010001. The second digit from the left of the Modbus address in the United States is used to indicate the type of component. The Modbus address of Siemens PLC is an address based on 0. In addition, an NI Alliance Partner SAPHIR has two released LabVIEW add-on products called ModBusVIEW over TCP and ModBusVIEW over Serial available on the LabVIEW Tools Network. It is an address based on 1, that is, the first address of similar components is 1. The Modbus API available through the LabVIEW Real-Time Module or the LabVIEW Datalogging and Supervisory Control (DSC) Module. The 40001 ~ 4xxxx described by the customer is the Modbus address used by American plicon company and ge company plc.
For example, a large server may be used to master a programmable logic controller (PLC) or.
The two characters on the left determine the data type, and the four characters on the right are the serial numbers in the data type. Interfacing of PLC with NI-LabVIEW using Modbus Protocol Pooja Panchal1, Prof. (3) Modbus address is a 6-character numeric value including data type and offset.