LCA*C Yokogawa CENTUM Control Processing Unit

Configured for high-speed network integration in Yokogawa CENTUM DCS platforms, the Yokogawa LCA*C (LCA Control Processing Unit) provides direct physical/electrical execution to run system logic and process algorithms. The unit functions as a centralized computing hardware component, interfacing directly with local backplane buses to route discrete and analog data streams without execution lag. It processes 4 channels of mixed signals and communicates over Vnet/IP, Modbus RTU/TCP, ASCII, and RS-485 network interfaces.

Suffix Breakdown & Model Matrix

Hardware Specifications

Channel-to-Channel Isolation and DCS Logic Processing

The LCA*C processing card executes real-time arithmetic calculations and schedules control loops across connected distributed control system nodes. To preserve frame timing and isolate transient spikes from field devices, the architecture incorporates channel-to-channel isolation across all signal conditioning stages. Incoming physical signals are decoded through dedicated Modbus and Vnet/IP memory registers to update process variable tables. This continuous galvanic isolation barrier protects the primary microprocessor from common-mode electrical noise and prevents systemic ground potential differentials from interfering with loop calculations.

Frequently Asked Questions

Q: What specific restrictions govern the online replacement or hot-swapping of the LCA*C control processor?

A: Online replacement requires the controller to operate within a configured redundant processor pair. Removing a single non-redundant module interrupts the system backplane bus, halting active control outputs and forcing connected I/O sub-modules into configured fail-safe states.

Q: How does the processor react if backplane logic voltage drops below the 5 VDC nominal rating?

A: The module contains an internal brownout detection circuit that continuously monitors input voltage rails. If logic voltage drops below operational thresholds, the hardware initiates a master reset, de-energizes command outputs, and illuminates the fault diagnostic LED.

Q: What communication protocols are natively supported for host and field data exchange?

A: The card natively supports Vnet/IP network communications alongside Modbus RTU, Modbus TCP, ASCII, and RS-485 serial interfaces for real-time register translation.

Field Installation Guidelines

1. Chassis Insertion Mechanics: Align module side guides with rack-mount slot guide rails prior to insertion. Slide the hardware firmly into the backplane connector block until locking mechanisms fully engage to prevent vibration-induced contact interruption.
2. Thermal Management: Maintain a minimum 50 mm clearance above and below the rack chassis assembly to facilitate natural air circulation. Ensure cabinet ambient temperatures remain within -20 to 60 deg C.
3. Shield Grounding: Terminate communication cable shielding at the cabinet entry bulkhead grounding strip. Route low-voltage signal lines away from high-voltage AC motor lines to suppress electromagnetic interference.