ICP DAS USA tET Series, Руководство пользователя

Страница: 84 / 118

Ethernet I/O Modules
6.2.3 03 (0x03) Read the Holding Registers (Readback AOs)
This function code is used to readback either the current values in the holding registers or the analog
output value from the PETL/tET/tPET module. These registers are also used to store the preset values
for the digital counter, the host watchdog timer, the module name and the TCP timeout, etc.
[Request]
Byte Description Size Value
00 Net ID (Station Number) 1 Byte 1 to 247
01 Function Code 1 Byte 0x03
02-03 Starting AO Address 2 Bytes
Refer to the Modbus Address Table for the
PETL/tET/tPET series .
(
Section 6.3 Modbus Register Table )
Byte 02 = high byte
Byte 03 = low byte
04-05
Number of 16-bit Registers
(Channels)
2 Bytes
Word Count
Byte 04 = high byte
Byte 05 = low byte
[Response]
Byte Description Size Value
00 Net ID (Station Number) 1 Byte 1 to 247
01 Function Code 1 Byte 0x03
02 Byte Count 1 Byte Byte Count of the Response (n=Points x 2 Bytes)
03~
Register Values
n Bytes
Register Values
n= 2; Byte 03 = high byte
Byte 04 = low byte
.......
n= m; Byte 03 = high byte
Byte 04 = low byte
.......
Byte m+1 = high byte
Byte m+2 = low byte
[Error Response]
Byte Description Size Value
00 Net ID (Station Number) 1 Byte 1 to 247
01 Function Code 1 Byte 0x83
02 Exception Code 1 Byte
Refer to the Modbus Standard Specifications for
more details
ICP DAS CO., LTD. PETL/tET/tPET DIO Series User Manual, Ver. 2.1, Sep. 2014, Page: 84
ГК Атлант Инжиниринг – официальный представитель в РФ и СНГ
+7(495)109-02-08 sales@bbrc.ru www.bbrc.ru