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ME31-XAAX0440_UserManul_EN
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2. AI channel sampling range parameter address is 0x04B2, register type is holding register, function code 0x06, 0x10.
When writing the AI channel sampling range parameter, if the parameter value 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 Modbus does not return an error command.
4.2.2 AI raw value and engineering value of analog input
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 function code is 0x04. The
value returned by this method is 2 bytes representing one channel, and the range of the value read is 0
～
4095. The
method of calculating the current is 0
～
4095 corresponding to 0
～
25mA. The register type is discrete input register,
and the read function code is 0x04. which is:
Current = (original value × 25)/4095 (mA)
2. Read the AI engineering value and directly convert to get the input current. The address of AI engineering value
register is 0x0064
～
0x0067, the register type is input register, and the read function code is 0x04. The value
returned by this method is 2 bytes representing 1 channel, and the value read is 0
～
25000. The method of
calculating the current is 0
～
25000 corresponding to 0
～
25mA. which is:
Current = engineering value / 1000 (mA)
4.2.3 Input filter parameters
The filter parameters of the AI channel can be set, the effective value is 1-16, and the default value is 6.
Filter parameter description:
1. All AI channels share one filter parameter. The higher the parameter value, the more stable the output value and the
slower the response.
2. AI channel filter parameter address is 0x04B0, and the register type is holding register. Function code 0x06, 0x10.
3. 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 does not return error commands.
4.2.4 Input calibration
[Note] If there is no professional calibration equipment, it is not recommended to calibrate, otherwise it will cause the
analog quantity acquisition error to become larger. The calibration method needs to be requested from the customer
service. It is recommended to back up the current calibration value before calibration.
4.3 Modbus gateway
The device can convert non-native Modbus instructions (converting Modbus TCP to Modbus RTU) and transmit them.
Theoretically, it can process up to 128 slave addresses simultaneously (limited by serial port access devices).
