Chengdu Ebyte Electronic Technology Co.,Ltd.
E78-470LN22S User Manual
Copyright ©2012–2021
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Chengdu Ebyte Electronic Technology Co.,Ltd.
16
This function of the host mode can realize the device cascading function and the data transmission between the 485 bus
and the network.
4.2 Basic functions of IO
4.2.1 Digital DO output
Read digital DO output
Function code: 01, read coil status
Address range: 00017(0x0010)~00022(0x0015)
Description: The equipment relay is passively output. When the coil is not energized, the relay NC port and COM port
are normally closed, and the NO port and COM port are normally open, and the value is 0; when the coil is energized, the
phenomenon is opposite, the relay NC port and COM port are disconnected Open, NO port and COM port are closed, the
value is 1. Query the relay status by command.
example:
Read the 6-channel switching output status, assuming the return value is 03, corresponding to the binary bit 0000 0011,
the lower six bits represent the switching output status, which are DO6, DO5, DO4, DO3, DO2, DO1 in sequence.
Modbus RTU protocol to read digital output:
send
01
01
00 10
00 06
BD CD
Device ModBus address
function
code
Switch start address
Number of read
switches
CRC
check
code
receive
01
01
01
03
11 89
