The VI returns the coil at Starting Address and each following coil up to Quantity. Quantity represents how many coils 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.
Labview 2013 modbus software#
Refer to your device's documentation to find the coil 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 coil to read. Use TCP Open Connection.vi to open a TCP connection. TCP Connection Refnum in is a network connection refnum that uniquely identifies the TCP connection. The MODBUS client sets this field in the request, and the server response must return this field with the same value.
Labview 2013 modbus serial#
It typically communicates to a MODBUS serial line slave through a gateway between an Ethernet TCP-IP network and a MODBUS serial line. Unit Identifier-This field is for intra-system routing purposes. Transaction Identifier-This identifier is for transaction pairing the MODBUS server copies the request transaction identifier in the response. This is additional information not usually required for a MODBUS transaction. MBAP Header is a cluster containing the transaction ID and Unit ID.
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