PXM PX340, Руководство пользователя

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EXAMPLE 1:
A query about 10 first DMX channels in hexadecimal notation reads as follows:
00 00 00 00 00 06 00 03 20 00 00 0A
PDU explained:
03
– Modbus function code: 03 or “Read Holding Registers”
20 00
– address of the register being read - 0x2000 = 8192 – corresponds to DMX output
channels
00 0A
– number of registers requested - 0x000A = 10 – DMX channels
Expected response:
00 00 00 xx 00 xx 00 xx 00 xx 00 xx 00 xx 00 xx 00 xx 00 xx 00 xx 00 00 00 17 00 03 14
Except for the “Length” field, the header is always the same as in the query.
The function code is copied from the query.
14
– 0x14 = 20 or the number of bytes read.
00 xx – the values of subsequent DMX channels, where xx is within the range 0x0000 to 0x00FF,
i.e. from 0 to 255.
EXAMPLE 2 :
Writing a value of 255 to the first Modbus register. The controller will treat the register as a
Modbus input channel. You can set the response of the controller to a change of value in the
channel in the tab “Input → Modbus” (see PXDesigner_M_ en manual, page 1 6 ).
00 00 00 00 00 06 00 06 00 00 00 FF
PDU explained:
06
– Modbus function code: 06 or “Write Single Register”
00 00
– r egister address 0x0000 = 0 (registers are addressed from 0)
00 FF
– c hannel value (range 0-255)
The controller will respond with the same message.
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