Configured for process signal integration in distributed control system architectures, the YOKOGAWA LC81*B (LC81*B RL-Bus Interface) provides direct physical signal processing and bus coupling. This hardware component serves as the primary network interface utilized to execute analog data exchange and bus management across industrial automation platforms.

Hardware Specifications

Signal Conditioning and Bus Connectivity

The LC81*B is engineered to translate standard 4-20 mA analog signals into digital data packets suitable for RL-Bus transmission. By providing a wide input voltage range (12 to 36 VDC), the module accommodates various field-side power configurations without requiring external signal conditioners. The card manages the high-speed digitization of analog process variables, ensuring that data transmitted to the control system maintains high resolution and minimal latency. Its robust operating temperature range (-20 deg C to +85 deg C) allows for deployment in high-heat industrial zones where standard electronics might otherwise experience thermal throttling or component failure.

Frequently Asked Questions (FAQ)

Q: Given that this model is typically available as used or refurbished, what diagnostic tests should be performed upon receipt?

A: Perform a loop-back test on the analog input channels using a precision current calibrator to verify accuracy. Additionally, inspect the edge connectors for signs of contact wear or corrosion, and verify that the module initializes without hardware error codes on the system bus.

Q: Is the 4-20 mA input isolated from the RL-Bus interface?

A: Yes, the LC81*B incorporates internal galvanic isolation to protect the bus circuitry from transient surges or ground loops present in the field-side analog wiring.

Field Installation Guidelines

• Analog Loop Integrity: When connecting 4-20 mA loops, ensure the loop impedance is within the rated limits of the LC81*B. Excessive loop resistance can cause signal clipping or "out-of-range" errors at the controller level.
• Thermal Management: Despite the wide temperature rating, install the card in an area with adequate airflow to prevent excessive heat buildup, which can impact the longevity of the internal analog-to-digital converter (ADC) components.
• Power Sequencing: Ensure the 12 to 36 VDC supply is stable and noise-free. Use shielded, twisted-pair cabling for the DC input to prevent electromagnetic interference (EMI) from inducing noise into the sensitive analog measurement stage.
• Grounding: Bond the module chassis to the system protective earth (PE) using a low-impedance connection. This is critical for maintaining signal accuracy and meeting electromagnetic compatibility standards in harsh industrial environments.