Use the Modbus Master VIs to create Modbus masters and to perform read and write operations on Modbus slaves.

Create Master Instance VI
Creates a serial or TCP Modbus master instance. You must manually select the polymorphic instance to use.
Close VI
Closes and destroys a Modbus master instance.
Property Node
Sets or writes properties for a Modbus master instance. Use this node to set the read operation timeout, write operation timeout, or both timeouts on a Modbus slave and to set the identification of a Modbus slave.
Read Holding Registers VI
Reads values from contiguous holding registers. The maximum number of holding registers this VI can read is 125.
Write Single Holding Register VI
Writes a value to a single holding register.
Write Multiple Holding Registers VI
Writes values to contiguous holding registers. The maximum number of holding registers this VI can write is 123.
Write and Read Multiple Holding Registers VI
Writes and reads values to and from contiguous holding registers. This VI performs the write operation before the read operation. The maximum number of holding registers this VI can write is 121. The maximum number of holding registers this VI can read is 125.
Mask Write Holding Register VI
Writes values to one or more bits of a holding register.
Read Coils VI
Reads values from contiguous coils. The maximum number of coils this VI can read is 2,000.
Write Single Coil VI
Writes a value to a single coil.
Write Multiple Coils VI
Writes values to contiguous coils. The maximum number of coils this VI can write is 1,968.
Read Discrete Inputs VI
Reads values from contiguous discrete inputs. The maximum number of discrete inputs this VI can read is 2,000.
Read Input Registers VI
Reads values from contiguous input registers. The maximum number of input registers this VI can read is 125.
Utilities
Use the Utilities VIs to read the identification and exception status of a Modbus slave, to set read and write operation timeouts on a Modbus slave, and to set the identification of a Modbus slave.

Parent topic: Modbus

LabVIEW Datalogging and Supervisory Control Module Programming Reference Manual