Chengdu Ebyte Electronic Technology Co., Ltd.
Distributed IO Host (M31 Series) User Manual
Copyright © 2012 , Chengdu Ebyte Electronic Technology Co., Ltd.
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4.4.2. AI input engineering quantity integer value and engineering quantity
floating point value
There are two ways to read the current signal size collected by the device:
(1) Read the AI engineering quantity shaping value and directly convert it to the input current. The starting
address of the AI engineering quantity integer value register is 0x00 00 , the register type is input register, and the
read function code is 0x04. The value returned by this method is one register representing one channel, and the
value read is 0~ 20000 . The method for calculating the current size is 0~20000 corresponding to 0~ 20mA . Right
now:
Current = engineering value / 1000 (mA)
(2) Read the floating point value of the AI engineering quantity and use the IEE754 conversion tool to convert
the hexadecimal data into a floating point number to obtain the input current. The starting address of the AI
engineering quantity integer value register is 0x0 3E8 , the register type is input register, and the read function code
is 0x04. This method returns two registers representing 1 channel.
4.4.3. AI filter parameters
The filter parameters of the AI channel can be set, the valid values are 1-16, and the default value is 6.
Filter parameter description:
(1) All AI channels share a filter parameter. The higher the parameter value, the more stable the output value and
the slower the response.
(2) The AI channel filter parameter address is 0x0DA 2 , and the register type is a holding register. Function codes
0x06, 0x10.
(3) When writing AI filter parameters, if the written parameter value is not within the range of 1 to 16, the closest
value will be automatically written. If the written filter parameter is 0, the device will use 1 as the filter parameter,
and Modbus does not return error instructions.
