Definition

For a read command, the data area of the master PLC is the destination of the data sent by the slave.

For a write command, the data area of the master PLC is the source of data.

For Modbus command codes 1, 2, 5 and 15, coding of bits is performed as follows:

  • Bits 1 to 16 are stored in the first item of the INT array set as argument, the first bit being in the least significant bit of the item.

  • Bits 17 to 32 are stored in the second item of the array, bit 17 corresponding to the least significant bit of the item.

  • Etc.

Thus, to exchange 1,000 bits, you must declare an array of 63 INT (1,000/16 + 8).

NOTE: A data area of integer type %MW may be used directly in the MasterDataArea parameter (for example: %MW100:50 designates an array of 50 integers starting at address 100).

A series of array items of type %M must first be converted and recopied in an array of integers (INT) according to the above-described coding.