LSIS XGL-EFMF, Руководство пользователя

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Chapter 8 Dedicated Communication
8-20
Modbus function and the maximum number of response data that Modbus TCP driver supports
are described in the table below. The correspondent master device shall make a request within
the range specified in the table. For example, Bit Read Request is available up to 2000 bits, and
Bit Write Request is up to 1600 bits.
Code Description Address Response Size
01 Read Coil Status hXXX 2000 Coils
02 Read Input Status 1XXXX 2000 Coils
03 Read Holding Registers 4XXXX 125 Registers
04 Read Input Registers 3XXXX 125 Registers
05 Force Single Coil hXXX 1 Coil
06 Preset Single Register 4XXXX 1 Register
15 Force Multiple Coils hXXX 1600 Coils
16 Preset Multiple Registers 4XXXX 100 Registers
[table 8.3.1] Modbus function code
Mapping of XG-T PLC memory is required for each function code’s request.
Respective setting details are as follows;
Item Description Remarks
DI area address XGT address applicable to digital input area Bit address
DO area address XGT address applicable to digital output area Bit address
AI area address XGT address applicable to analog input area Word address
AO area address XGT address applicable to digital output area Word address
The address value specified in each item is the base address of the applicable area.
Fig 8.3.1 shows that DI area is assigned starting from PX0000 and that AO area is assigned
starting from PW300.
The input value of the base address shall be within the effective areas of %M, P, etc. Since
Modbus address is 1 ~ 9999 (decimal), the size of the bit I/O area will be 9999/8 = 1249.875
bytes. In addition, the size of the word I/O area will be 9999*2 = 19998 bytes.
If the user sets the base address of the bit output (hXXX) area to 0, Modbus bit area 00001 will
be correspondent to 0 th byte, 0 th bit, and 00002 to 0 th byte, 1 st bit.