Application Scenarios
Process acquisition (4-20mA) pressure, liquid level, temperature transmitter (with 4-20mA output).

The module comes with a 250 Ω resistor inside, which can be directly connected to a two-wire transmitter without the need for an external resistor; Open the disconnection diagnosis, and the PLC reports a fault when the transmitter is disconnected.

Voltage signal acquisition: ± 10V/0-10V potentiometer, valve position feedback, frequency conversion/servo analog output signal.

Differential wiring, try to shorten cables as much as possible to reduce interference.

Large point analog centralized acquisition machine with 8 channels and ALG440/ALG441 expansion, with a maximum of 120 AI channels in the entire set, occupying only one slot on the PLC mainframe.

Attention: Expansion module cables should not be too long; The expansion submodule does not occupy the PLC backplane slot.

Engineering pit point
There is no isolation between channels, and multiple transmitter power supplies share the same ground, resulting in reading drift and jumping. 👉 Countermeasure: Add signal isolators; The transmitter should be powered independently as much as possible.
Do not confuse with IC697ALG231
ALG230: Scalable, no channel isolation, suitable for multiple points and limited budget
ALG231: Channels are isolated from each other and cannot be connected to expansion modules. It has strong anti-interference ability and is fixed at 8 points per module
Expand ALG440/441. Note that ALG230 is the only main module, and the expansion submodule only performs signal conversion and cannot be used separately on the rack.
The software must be configured with the correct range and hardware wiring. If the software range is selected incorrectly, the reading will jump around; No hardware dialing.
Not suitable for high-speed closed-loop control in scenarios (insufficient module refresh rate); It is not recommended to use strong electromagnetic interference directly on site, and additional isolation should be added.
Simple application example of the program
Select the module model for hardware configuration, set each channel to 4-20mA, and enable wire breakage detection.
The original value is stored in the% AI register with a 16 bit complement.
PLC program for engineering quantity conversion: 4mA corresponds to a value of 5530, 20mA corresponds to 27648, converted to engineering units (bar, m, ℃).

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