Chengdu Ebyte Electronic Technology Co.,Ltd.
【2DI + 2AI + 4DO】MA02-AACX2240 User Manual
Copyright ©2012–2021
，
Chengdu Ebyte Electronic Technology Co.,Ltd.
14
4 Product Features
4.1 Analog input AI
4.1.1 Analog input AI description
The analog input AI measures the current signal, the acquisition range is 0-20mA or 4-20mA, the accuracy is 3
‰
,
and the resolution is 12 bits. Adopt single-ended input, sampling frequency 10Hz, input impedance 100
Ω
.
4.1.2 Analog input AI filter parameters
The filter parameters of the AI channel can be set, the effective value is 1-16, and the default is 6.
Note:
(1) AI channel filter parameter is a filter parameter shared by all AI channels. The larger the filter parameter, the
stronger the anti-interference ability of AI sampling, but at the same time it has time delay.
(2) AI channel filter parameter address is 0x04B0, and the register type is holding register. Function code 0x06,
0x10. When writing AI filter parameters, if the written parameter value is not within the range of 1-16, it will
automatically take the closest value to write. If the write filter parameter is 0, the device will take 1 as the filter parameter,
and Modbus will not return. Wrong instruction
4.1.3 Analog input AI sampling range
Set the sampling range of all AI channels, valid values are 1 and 0 (default 0).
0: Represents 0
～
20mA
1: Represents 4
～
20mA
(1) The AI sampling range is shared by all channels. When the AI channel sampling range is configured for
4-20mA sampling, if the current signal is lower than 4mA, the engineering value of the channel is converted to 0. For
signals greater than 20mA, there is no conversion limit, but it cannot exceed 25mA (there is a risk of equipment damage
if it exceeds 25mA).
(2) AI channel sampling range parameter address is 0x04B2, the register type is holding register, function code
0x06, 0x10. When writing the AI channel sampling range parameter, if the value of the parameter written is not within
the range of 0 to 1, it will automatically take the closest value to write. For example, if the write sampling range
parameter is 2, the device will take 1 as the sampling range parameter. And MDOBUS does not return an error command
4.1.4 Analog input AI raw value, engineering value
There are two ways to read the magnitude of the current signal collected by the device:
(1) Read the original value of AI and calculate the input current based on the input impedance.
The address of the AI original value register is 0x0000
～
0x0003, the register type is input register, and the read
