![]() ![]() Timeout specifies the maximum time period, in milliseconds, that the VI waits for the slave's response before throwing an error.Įrror in describes error conditions that occur before this VI or function runs. The VI returns the holding register at Starting Address and each following holding register up to Quantity.For example, if Starting Address is 0 and Quantity is 4, the VI reads holding registers from the slave at address 0, 1, 2, and 3. Quantity represents how many holding registers to read from the slave. For example, a register name defined as 2 in a MODBUS configuration device translates to register address 1 in the Holding Registers table of the LabVIEW MODBUS library, as shown below. The MODBUS LabVIEW library expects register addresses, not register names, so you may need to subtract 1 from the address you defined in the MODBUS device configuration software. Per MODBUS convention, the register address of the slave device is calculated by subtracting 1 from the register name that you specify in the master device configuration software. In most MODBUS device configuration software, you must enter a name for the register you want to use. Refer to your device's documentation to find the holding register address mapping.īe sure to specify the correct address in the MODBUS device configuration software for the register you want to use in LabVIEW. This address is sometimes referred to as offset. Starting Address is the first address location of the holding register to read. For more information about VISA resource names, refer to the NI-VISA Help. This control also specifies the session and class. ![]() VISA resource name specifies the resource to be opened. Note: Consult your device documentation to find out how to validate/change the address of your device. This property is usually valid for RS-485 networks, which can have multiple MODBUS devices connected to the same network. This is the address of the slave you are communicating with. ![]()
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