Serial Port Auto Polling; Configuration Instructions - Ebyte E90-DTU User Manual

Chengdu Ebyte Electronic Technology Co., Ltd.

4.7 Serial port auto polling

When the device is in slave mode, it supports configuring multiple polling commands for automatic collection.
The command length can be configured up to 20 bytes. It supports a variety of serial port protocols (RS485 and
3.3V-TTL cannot be used at the same time), and the collection cycle and command interval can be flexibly
configured. Query interval, support automatic verification of Modbus-CRC (open by default).

4.7.1 Configuration instructions

The automatic polling instruction table starts from the holding register (0x1838), and there is a set of polling
instruction data for every 13 registers (one register is 2 bytes), and supports configuration of up to 10 instructions.
The details of the register bits are as follows:
register 1
overtime time
instruction
length
milliseconds
Command length: range (0x01-0x14), indicating the length of the command data, for example, to configure
the Modbus command "0x010100000008", you need to configure the length to 0x06;
Timeout time: the configured command wait time for response, and start the command interval timer after the
timeout. This parameter has the same meaning as the Modbus timeout time. The configured time needs to be
consistent with the request waiting time. For example, the Modbus request needs to be configured with the timeout
of the PLC/HMI/PC. The time is the same.
Command interval: the interval for sending the next command after sending one command is completed;
Instruction content: store the instruction in hexadecimal, up to 20 bytes can be stored:
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A set of 13 registers
register 2 register 3
instruction
interval
>0 start, in
0-255ms
0-65535ms
E90-DTU(400SL30L)_UserManual_EN
Register 4 - Register 13 (stores Modbus commands)
Command content (hexadecimal), up to 20 bytes
20