Modbus RTU protocol for WXT530 - WXT530

WXT530 Series User Guide

Document code
English (United States)
Document type
User guide
WXT530 Modbus communication is based on Modbus Application Protocol Specification V1.1b3
Modbus RTU is available for Vaisala Weather Transmitter WXT530 Series from firmware version 3.85 onwards.

Ordering new WXT530 with Modbus

To order the RS-485 Modbus option, use the order code WXT53XUXXXXXXXXXX.

To use Modbus with an existing WXT530, see Using Modbus with old WXT530.

To change port settings, see Changing port settings.

WXT530 default Modbus settings

CLI is the command line interface, such as ASCII, NMEA and SDI-12.

Vaisala WXT530 Configuration Tool works only in the CLI mode. To use Vaisala WXT530 Configuration Tool, change from Modbus mode to CLI mode first. See Changing from Modbus mode to CLI mode.

When you order WXT530 with Modbus, the default settings are the following:

Table 1. WXT530 default Modbus settings

WXT530 CLI mode

WXT530 Modbus mode

User port ASCII polled 1 Modbus RTU
Service port 2 RS-232 19200, 8, N, 1 RS-232 19200, 8, N, 1
Default address 0 1
You can change WXT530 Modbus address by typing the new address to the holding register number 10 (0x0009).

To change the Modbus address in the CLI mode, see Changing Modbus address in CLI mode.

To use the Modbus protocol:

The polling frequency must not be higher than the corresponding update interval. For example, 1 minute for average values.

1 Applies when you move from Modbus mode to CLI mode.
2 RS-232 19200, 8, N, 1 is the fixed service port setting for all WXT530 communication interface options.

Note that parallel use of user port and service port is not supported.