AAI143-S50/K4S00

The Yokogawa AAI143-S50/K4S00 is a 16-channel isolated analog input module designed to receive 4-20 mA signals from field transmitters. It supports channel-level selection of 2-wire or 4-wire transmitter configurations, with built-in transmitter power supply and HART communication capability. Its 10 ms data update period supports regular acquisition of process signals for control system monitoring.

Input Channels and Signal Processing

The module provides 16 electrically isolated input channels, each accepting a 4-20 mA current signal. The allowable input current is 24 mA, while the input accuracy is specified as +/-16 uA.

The 10 ms data update period defines the interval for refreshing acquired input data. This parameter is relevant when assessing the module's signal acquisition characteristics within a control system.

Transmitter Connection and Power Supply

Each channel can be configured for a 2-wire or 4-wire transmitter using a setting pin. This allows the input configuration to be selected according to the connected field instrument's wiring arrangement.

For 2-wire transmitter applications, the module provides a transmitter power supply with an output current limit of 25 mA. The specified voltage is at least 19.0 V at 20 mA and no more than 25.5 V at 0 mA. These conditions should be considered when checking transmitter voltage requirements and loop loading.

Electrical Isolation and Input Resistance

The module withstands 1500 V AC for 1 minute between the input circuit and the system. This isolation specification defines the tested withstand condition between these circuit sections.

Input resistance depends on the module's power state and input current. With power ON, it ranges from 270 ohms at 20 mA to 350 ohms at 4 mA. With power OFF, the input resistance is 500 kohms or greater.

HART Communication and External Connections

HART communication is supported, allowing compatible field devices to exchange digital communication over the analog current loop. The module's 4-20 mA input function remains the basis for process signal acquisition.

External connections are available through pressure clamp terminals, MIL connector cables, or the dedicated KS1 cable. The selected connection arrangement should match the installed terminal and cabling configuration.

Technical Specifications

Parameter	Specification
Model	AAI143-S50/K4S00
Brand	Yokogawa
Product Type	Analog Input Module
Number of Input Channels	16, isolated
Input Signal	4-20 mA
Allowable Input Current	24 mA
Input Accuracy	+/-16 uA
Data Update Period	10 ms
Input Resistance (Power ON)	270 ohms at 20 mA; 350 ohms at 4 mA
Input Resistance (Power OFF)	500 kohms or greater
Withstanding Voltage	1500 V AC, 1 minute, input-to-system
Transmitter Power Supply	At least 19.0 V at 20 mA; maximum 25.5 V at 0 mA
Transmitter Supply Current Limit	25 mA
Transmitter Configuration	2-wire or 4-wire, selectable per channel
HART Communication	Available
Ambient Temperature Drift	+/-16 uA/10 deg C
Maximum Current Consumption (5 V DC)	230 mA
Maximum Current Consumption (24 V DC)	540 mA
External Communication Connection	Pressure clamp terminal, MIL connector cable, dedicated KS1 cable
Weight	0.3 kg

Frequently Asked Questions

Q: Can the AAI143-S50/K4S00 connect to both 2-wire and 4-wire transmitters?

A: Yes. The module supports both transmitter arrangements, with the configuration selected independently for each channel using a setting pin. The wiring and power supply arrangement must correspond to the connected transmitter.

Q: Does this module support HART communication?

A: Yes. HART communication is specified as available. The connected field device and loop configuration must also support HART communication.

Q: What should be checked when replacing an existing AAI143 module?

A: Verify the complete model designation, channel configuration, transmitter wiring, external connector type, and HART requirements. The specified 1500 V AC isolation withstand condition and transmitter supply limits should also be checked against the existing installation.

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