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ModbusReadFloat (Function) In french: ModbusLitFlottant Reads one or more single-precision floats from a Modbus slave, starting at a specific address.  New in version 2024
Session is modbusSession
Session = ModbusConnectTCP("192.168.1.7")
arrResponse is array of 5 4-byte int
IF ErrorOccurred = True THEN
Trace(ErrorInfo())
ELSE
arrResponse = ModbusReadFloat(Session, 0x42, 5, False, modbusABCD)
IF ErrorOccurred = True THEN
Trace(ErrorInfo())
END
END
ModbusDisconnect(Session)
Syntax
Reading 1 single-precision float from a Modbus slave Hide the details
<Result> = ModbusReadFloat(<Session> , <Address> , <Read-only> , <Endianness>)
<Result>: Real Float value read. <Session>: modbusSession variable Name of the modbusSession variable that corresponds to the communication session with the Modbus slave. <Address>: Integer Address of the float in the slave (between 0 and 65,535). <Read-only>: Boolean - True if the floats to be read are part of read-only data (Modbus function code 4 (Read Input Registers)).
- False if the floats to be read are part of read-write data (Modbus function code 3 (Read Multiple Holding Registers)).
<Endianness>: Integer constant Mode for storing float values on the slave device. Bytes are identified from A to D. A is the most significant byte and D is the least significant byte (IEEE-754 standard). | | | modbusABCD | The sent bytes are stored the same order on the slave device. | | modbusBADC | The sent bytes are swapped 2 by 2 on the slave device. | | modbusCDAB | The sent bytes are swapped 2 by 2 on the slave device. | | modbusDCBA | The sent bytes are swapped on the slave device. |
Reading multiple single-precision floats from a Modbus slave Hide the details
<Result> = ModbusReadFloat(<Session> , <Address> , <Number of floats> , <Read-only> , <Endianness>)
<Result>: Array Array of reals that contains the value of the floats read. <Session>: modbusSession variable Name of the modbusSession variable that corresponds to the communication session with the Modbus slave. <Address>: Integer Starting address of the floats in the slave (between 0 and 65,535). <Number of floats>: Integer Number of floats to be read (to be sent by the slave). <Read-only>: Boolean - True if the floats to be read are part of read-only data (Modbus function code 4 (Read Input Registers)).
- False if the floats to be read are part of read-write data (Modbus function code 3 (Read Multiple Holding Registers)).
<Endianness>: Integer constant Mode for storing float values on the slave device. Bytes are identified from A to D. A is the most significant byte and D is the least significant byte (IEEE-754 standard). | | | modbusABCD | The sent bytes are stored the same order on the slave device. | | modbusBADC | The sent bytes are swapped 2 by 2 on the slave device. | | modbusCDAB | The sent bytes are swapped 2 by 2 on the slave device. | | modbusDCBA | The sent bytes are swapped on the slave device. |
Remarks - This function blocks the application until the slave responds to the message or until the session timeout is exceeded.
- After calling ModbusReadFloat, it is recommended to check the ErrorOccurred variable to make sure there are no errors.
Business / UI classification: Business Logic
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