Description

Yokogawa AST143 Execution Control Package

The Yokogawa AST143, also cataloged as the AST143 Execution Control Package, operates as a dedicated hardware component for analog signal acquisition and 4-20 mA current output control within CENTUM VP and CENTUM CS 3000 systems. It manages thermocouple, RTD, and millivolt inputs while providing deterministic execution and HART communication support.

Hardware Specifications

Parameter	Specification
ModelBrand	Yokogawa AST143
Origin	Japan
Weight	1.2 kg
Dimensions	220 mm x 100 mm x 120 mm
OperatingTemp	-20 to 70 degC
PowerConsumption	24 VDC ±10%, 80 mA at 24 VDC, 150 mA at 5 VDC
InputTypes	Thermocouple (TC), Millivolt (mV), RTD, Thermistor
NumberofChannels	16
InputRange	TC: -200 to 1500 degC; RTD: -200 to 800 degC; Thermistor: -50 to 150 degC
Output	4-20 mA
Accuracy	±0.2% of span
CommunicationProtocol	HART
Isolation	Built-in isolated barrier
WithstandingVoltage	1500 VAC between circuits and channels
InputResistance	≥1 MΩ
DataUpdatePeriod	10 ms
ReferenceJunctionCompensation	±1 degC
DriftDueToAmbientTemp	TC: ±125 μV/10 degC; mV: ±250 μV/10 degC

Process Control And DCS Features

• Supports channel-to-channel isolation to prevent signal interference across analog inputs.
• Cold junction compensation (CJC) is implemented for thermocouple channels, maintaining ±1 degC reference accuracy.
• HART protocol is supported on all 4-20 mA outputs for device diagnostics and configuration without interrupting loop operation.
• Compatible with FOUNDATION Fieldbus and Profibus PA systems for expanded connectivity.

Frequently Asked Questions

Q: Does the AST143 support hot-swappable installation?
A: Hot-swapping is not recommended. All analog input wiring and power must be disconnected prior to module replacement to avoid signal disturbance.

Q: What is the maximum loop resistance supported for 4-20 mA outputs?
A: Standard 4-20 mA loop resistance limits apply; typical field wiring up to 500 Ω is supported without degrading signal accuracy.

Q: Can firmware be updated in the field?
A: Firmware updates must be performed according to Yokogawa CENTUM VP/CS 3000 maintenance procedures to avoid execution disruption.

Field Installation Guidelines

• Mount module vertically in the rack to ensure proper ventilation.
• Maintain at least 20 mm spacing between analog input cables and high-voltage power lines to reduce EMI.
• Connect shielded analog signal cables to the designated earth terminals to minimize noise coupling.
• Verify isolated barrier integrity before powering the module to prevent cross-channel voltage faults.
• Route input and output cables separately and avoid looping or crossing with AC mains wiring.

Specifications

• Brand: Yokogawa

Advantages

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