Description

Yokogawa AAI135-H00/K4A00 Analog Input Module

TheYokogawa AAI135-H00/K4A00，also cataloged as theAAI135Analog Input Module, operates as a dedicated hardware component for 4-20 mA current signal acquisition within DCS analog input processing networks. Configured for field current loop termination and HART superimposed digital communication decoding, theYokogawa AAI135-H00/K4A00(AAI135Analog Input Module) provides direct physical/electrical execution.

Suffix Breakdown & Model Matrix

• AAI135: Base model, 8-channel isolated 4-20 mA analog input module
• H00: Basic configuration set with HART communication support enabled via module interface
• K4A00: KS cable interface adapter option, compatible with ATK4A-00 termination assembly

Hardware Specifications

Parameter	Specification
ModelBrand	Yokogawa AAI135-H00/K4A00
Origin	Japan
Weight	0.3 kg
Input Signal	4-20 mA
Channels	8-channel, isolated
Allowable Input Current	25 mA
Withstanding Voltage	500 V AC (input-system, 1 min); 500 V AC (channel-channel, 1 min)
Input Resistance	290 ohm (20 mA, power ON) to 450 ohm (4 mA, power ON); >= 500 k ohm (power OFF)
Accuracy	+/- 16 uA
Communication	HART protocol overlay supported

Process Signal Conditioning and HART Loop Handling

The module implements HART protocol superimposition on 4-20 mA analog loops, enabling simultaneous analog measurement and digital field device communication without signal separation hardware. Channel-to-channel galvanic isolation reduces inter-channel electrical coupling under mixed-loop termination conditions, maintaining stable current acquisition across all 8 inputs in dense I/O configurations.

Frequently Asked Questions

Q: Does the module support hot-swap replacement under live backplane power?
A: Hot-swap capability depends on system rack design; electrical isolation is maintained per channel, but backplane behavior is system-defined.

Q: What is the effect of HART communication on 4-20 mA measurement accuracy?
A: HART signal is superimposed at low amplitude frequency; analog current measurement remains within specified +/- 16 uA accuracy band.

Q: Can unused channels be left open-circuit?
A: Open channels should follow termination guidelines to avoid noise pickup; input resistance in power OFF state is >= 500 k ohm.

Field Installation Guidelines

• Maintain correct polarity for each 4-20 mA loop connection at terminal interface
• Use shielded twisted pair wiring for all analog input channels
• Ground cable shields at a single-point earth reference to avoid ground loop currents
• Ensure KS cable interface adapter ATK4A-00 is fully seated before energizing system
• Avoid routing analog input wiring parallel to high-voltage or switching power lines
• Verify channel isolation integrity before commissioning multi-loop installations

Specifications

• Brand: Yokogawa

Advantages

• High reliability in industrial environments
• Supports continuous operation
• Compatible with major PLC/DCS systems