AAI135-S03/K4A00

The Yokogawa AAI135-S03/K4A00 is an 8-channel analog input module designed to receive 4-20 mA signals from field instruments and convert them into digital data for control system processing. It features isolated input channels, the ISA Standard G3 option, an extended operating temperature option, and a KS Cable Interface Adapter configuration identified by /K4A00.

Input Function and Channel Isolation

The AAI135 accepts 4-20 mA analog current signals from field transmitters and converts them into internal digital values for use by the control system. Its eight input channels are electrically isolated from one another, helping prevent electrical interference or potential differences on one field circuit from directly affecting other input channels.

This configuration is suitable for acquiring independent process measurements, such as transmitter current signals, where channel isolation is required. The standard -S version does not indicate the HART communication option; Yokogawa identifies -H separately for HART-equipped versions.

Ordering Code and Configuration

The complete ordering number identifies both the module configuration and its connection arrangement:

• AAI135: 8-channel, isolated 4-20 mA analog input module.
• -S: Standard type.
• 0: Basic type.
• 3: ISA Standard G3 option and extended temperature option (-20 to 70 deg C).
• /K4A00: KS Cable Interface Adapter, model ATK4A-00.

The /K4A00 suffix identifies the specified cable interface adapter configuration. It should not be confused with a pressure-clamp terminal block option, which uses a different ordering code.

Electrical and Performance Characteristics

The module provides isolated signal acquisition between the field and the control system, as well as between individual input channels. Yokogawa specifies a withstand voltage of 500 V AC for 1 minute between the input and system, and between input channels. This isolation is relevant when field transmitters operate on separate electrical circuits or have different ground potentials.

The input circuitry supports 2-wire and 4-wire transmitter connections. For 2-wire transmitters, the module provides a minimum terminal voltage of 15.0 V at 20 mA, subject to external wiring voltage drop. The input resistance varies with signal current because of the input protection circuit.

Parameter | Specification

Parameter	Specification
Model	AAI135-S03/K4A00
Brand	Yokogawa
Product Type	Analog Input Module
Number of Input Channels	8
Input Signal	4-20 mA DC
Channel Isolation	Isolated channels
Allowable Input Current	25 mA
Input Resistance	290 Ohm at 20 mA to 450 Ohm at 4 mA
Input Accuracy	+/-16 uA
Data Update Period	10 ms
Transmitter Supply Voltage	15.0 V minimum at 20 mA; 29.3 V maximum at 0 mA
Maximum Current Consumption	360 mA at 5 V DC; 450 mA at 24 V DC
Isolation Withstand Voltage	500 V AC for 1 minute
HART Communication	Available on HART-equipped version; not specified for -S type
Operating Temperature Option	-20 to 70 deg C
ISA Environmental Option	ISA Standard G3
External Connection	KS cable interface adapter
Adapter Model	ATK4A-00
Weight	0.30 kg

System Configuration and Application

The AAI135 belongs to Yokogawa's analog I/O hardware for FIO systems. It receives field current signals and makes the converted values available to the Field Control Station (FCS) for monitoring, process calculations and control logic.

The module is also specified for dual-redundant configuration. When evaluating a replacement, the existing module type, connection adapter, field wiring arrangement and system hardware configuration should be checked together rather than matching only the basic AAI135 model number.

Frequently Asked Questions

Q: How many field signals can the AAI135-S03/K4A00 receive?

A: It supports eight independent 4-20 mA DC analog input channels. Each channel has electrical isolation from the other input channels.

Q: Does the AAI135-S03/K4A00 support HART communication?

A: The -S suffix identifies the standard type. Yokogawa identifies -H separately for the HART communication version. The HART capability of the -S configuration should therefore not be assumed.

Q: What does the /K4A00 suffix identify?

A: It specifies the KS Cable Interface Adapter configuration using adapter model ATK4A-00. This is part of the connection arrangement and should be checked when matching the module to existing system wiring. 

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