DS3800HLCB | GE Turbine LVDT Signal Conditioner Board

Description

Product Introduction

The DS3800HLCB is an enhanced version of the LVDT/RVDT input board—it includes diagnostic features that provide additional visibility into the health of the LVDT sensors and the signal conditioning circuits. This board processes position feedback signals from LVDT and RVDT sensors, providing the 120V AC excitation and conditioning the return signals for accurate position feedback. The diagnostic features include open-circuit detection, short-circuit detection, and sensor health monitoring, making it easier to troubleshoot position feedback issues.

We’ve used the HLCB in a turbine control application where valve position feedback was critical for fuel control. The diagnostic features allowed us to detect a failing LVDT sensor before it caused a control issue, enabling us to replace it during a scheduled outage. The board’s ±0.1% position accuracy and diagnostic capabilities made it a valuable asset for the plant’s maintenance program.

Key Technical Specifications

Compatible Replacement Models

Frequently Asked Questions (FAQ)

Q: What diagnostics does the HLCB provide compared to the HLCA?
A: The HLCB provides per-channel open-circuit detection, short-circuit detection, and sensor health monitoring. The diagnostics are reported via the backplane and via bi-color LEDs on the board. This allows you to detect a failing sensor, a broken wire, or a shorted sensor before it causes a control issue. The HLCA has no such diagnostics.

Q: How do the diagnostic LEDs work on the HLCB?
A: The HLCB uses bi-color LEDs (green/red). Green indicates the channel is functioning normally. Red indicates a fault condition—open circuit, short circuit, or a sensor health issue. This provides immediate visual feedback for troubleshooting, making it easier to identify and resolve position feedback issues.

Q: What type of LVDT sensors does the HLCB support?
A: The HLCB supports standard 120V AC-excited LVDT and RVDT sensors used in turbine control applications. The board provides the 120V AC excitation and conditions the secondary voltages to provide a position feedback signal. The board’s input impedance (10kΩ) is compatible with most industrial LVDT sensors.

Q: What’s the accuracy of the position measurement on the HLCB?
A: The HLCB provides position measurement with an accuracy of ±0.1% of full scale. This is sufficient for most turbine valve position control applications. The board uses precision signal conditioning circuitry to ensure accurate position feedback.

Q: Does the HLCB have conformal coating?
A: Not by default. The HLCB’s suffix typically indicates termination type, not coating. If you need conformal coating for harsh environments, look for a suffix with a “G” (e.g., DS3800HLCB1G1G). The standard HLCB is suitable for indoor environments. If your plant has high humidity or corrosive conditions, consider a coated variant.

Q: What’s the backplane current draw of the HLCB?
A: The HLCB draws 1.3A from the 5V backplane rail, which is 0.1A more than the HLCA (1.2A). The extra current is for the diagnostic circuitry. The Mark V power supply is rated at 6A on the 5V rail, so the HLCB is within the limit. If your rack has multiple HLCB boards, check your total backplane current. We recommend keeping total backplane current below 5.5A for margin.

Q: Can I use the HLCB with LVDT sensors from different manufacturers?
A: The HLCB is designed for standard 120V AC-excited LVDT sensors. Most industrial LVDT sensors from major manufacturers (e.g., Schaevitz, Solartron) are compatible. However, always verify the sensor’s excitation requirements and output characteristics before installation. Consult the sensor data sheet and compare with the HLCB specifications. The diagnostic features on the HLCB are compatible with most standard LVDT configurations.

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