Yokogawa ASI133 Analog Input Module

The Yokogawa ASI133, also cataloged as the ASI133 Analog Input Module with Built-In Barrier, serves as the primary ASI133 Analog Input Module with Built-In Barrier utilized to execute high-density intrinsically safe data collection across Centum VP control system platforms. It provides direct physical and galvanic termination for up to eight hazardous-area 4 to 20 mA analog transmitters without requiring external marshalling isolation barriers.

Suffix Breakdown & Model Matrix

The ASI133 series incorporates protective hardware options and environmental ruggedization metrics directly into its ordering specification:

• ASI133: Core product designator for the 8-channel, fully isolated Analog Input Module.
• Built-In Barrier: Integrated intrinsic safety (Ex i) energy-limiting hardware circuitry.
• ISA Standard G3 Option: Advanced chemical corrosion resistance conformance coating for harsh atmospheric conditions.
• Temperature Option: Extended thermal operating bounds certified for continuous deployment from -20 to 70 deg C.

Hardware Specifications

Distributed Process Control & Fieldbus Topologies

• 4-20 mA HART Loop Protocol and Fieldbus Routing Layer The module manages local communication bus density, digitizing physical process telemetry from hazardous area field arrays. It processes 4-20 mA HART digital variables overlaying the analog signal path, parsing the configuration data streams before packet encapsulation to ensure error-free transmission over the primary DCS backplane bus.
• Channel-to-Channel Isolation and Optical Safety Controls Internal circuit paths integrate galvanic isolation blocks to interrupt high-voltage transients between the power rails, logical bus elements, and adjacent I/O sub-assemblies. This prevents localized field ground loops from compromising backplane stability and eliminates electrical crosstalk across high-density signal channels.

Frequently Asked Questions

Q: How do the built-in intrinsic safety barriers affect the external loop power calculations for field transmitters?

A: The integrated barriers introduce an internal series safety resistance to limit fault energy under abnormal field conditions. Engineers must include this fixed internal safety impedance drop when calculating the total loop resistance to ensure the field transmitter receives at least its minimum rated operating voltage at a full 20 mA signal output.

Q: What are the online hot-swap restrictions for the ASI133 module within a hazardous environment node?

A: The module supports live online hot-swapping when seated into a redundant baseplate configuration. Because the energy-limiting components are contained entirely inside the module chassis, the physical removal of the card does not break the intrinsic safety integrity of the field wiring loops.

Field Installation Guidelines

• Chassis Alignment, Card Slot Seating, and Retention Lock Align the module circuit board edge cleanly with the designated slot tracks of the node baseplate. Slide the unit inward until the rear pins seat completely into the passive backplane socket, then secure the integrated mechanical locking fasteners to prevent shifting from structural cabinet vibration.
• Hazardous-Area Signal Routing and Shield Grounding Blocks Route all intrinsically safe field cables through dedicated, isolated wireways completely separate from non-intrinsically safe power and control wiring. Strip the multi-conductor analog cable shields back cleanly and terminate the drain wires directly onto the dedicated instrument earth ground bus bar to eliminate noise and maintain safety barrier baseline grounding potentials.