DS3800HFPG | OEM GE Turbine Speed Input Module

Description

Product Introduction

The DS3800HFPG is the smart version of the frequency input board, adding diagnostics to the 24V DC pulse input capability of the HFPC. This board detects signal presence and frequency validity on each channel, giving you visibility into the health of your speed sensors and wiring. If you’ve been plagued by intermittent speed sensor failures or wiring faults that cause nuisance trips, the HFPG provides the diagnostic data to pinpoint the issue. The diagnostics are accessible via the Mark V’s I/O status registers, allowing you to monitor sensor health remotely.

We’ve used the HFPG in a plant where speed sensor failures were causing unexplained overspeed trips. The board’s diagnostic data revealed that one sensor had intermittent signal dropout due to a loose connector—the frequency validity flag showed “invalid” when the signal dropped. We traced it to a loose terminal and tightened it, eliminating the trips. The 24V DC input capability matched our proximity sensors, and the diagnostics gave us confidence in the signal integrity. The HFPG is a significant upgrade for plants where frequency measurement reliability is critical.

Key Technical Specifications

Compatible Replacement Models

Frequently Asked Questions (FAQ)

Q: What diagnostics does the HFPG provide compared to the HFPC?
A: The HFPG provides per-channel signal presence detection (is there a pulse?) and frequency validity monitoring (is the frequency within a valid range?). The diagnostics are reported via the backplane, so the Mark V controller can read the status of each frequency input. This allows you to detect a failed sensor, a broken wire, or a sensor that’s not producing a valid signal. The HFPC has no such diagnostics.

Q: How do the diagnostic LEDs work on the HFPG?
A: The HFPG uses bi-color LEDs (green/red). Green indicates a valid signal is present on the channel. Red indicates a fault condition—either no signal (sensor failure or wiring open) or an invalid frequency (signal too high or too low). This provides immediate visual feedback for troubleshooting, a significant improvement over the green-only LEDs on the HFPC.

Q: Can I use the HFPG with a proximity sensor that outputs a 24V DC pulse?
A: Yes, the HFPG is designed for 24V DC pulse inputs. Proximity sensors typically output a voltage pulse when a target passes, which the HFPG counts. The board’s input voltage range (10-30V DC) covers standard 24V DC sensors.

Q: What’s the frequency range of the HFPG?
A: The HFPG measures frequencies from 0Hz to 10kHz, with ±0.1% accuracy. This covers the typical speed range of 60Hz turbines (up to 7.2kHz for a 120-tooth gear). The 12-bit resolution provides a count value for the Mark V to calculate speed. If you need higher frequencies (up to 100kHz), consider other frequency input variants.

Q: Does the HFPG require a software update to use the diagnostics?
A: Yes. The HFPG’s diagnostics are mapped to the Mark V’s I/O status registers. You’ll need to update your Mark V configuration to read these registers. The specific register mapping is in GE’s application manual (GEI-100873). It’s a straightforward update—typically about 1-2 hours of configuration work. If you’re upgrading from an HFPC, you’ll also need to update the controller’s hardware configuration to recognize the HFPG.

Q: The HFPG has a 0.9A backplane current draw. Is that higher than the HFPC?
A: Yes, the HFPG draws 0.9A, which is 0.1A more than the HFPC (0.8A). The extra current is for the diagnostic circuitry. If your rack is near the power supply limit, this small increase could be significant. The Mark V power supply is typically rated at 6A on the 5V rail. If you have multiple HFPG boards, check your total backplane current. We recommend keeping total backplane current below 5.5A for margin.

Q: Does the HFPG have conformal coating?
A: Not by default. The HFPG’s suffix typically indicates termination and fusing, not coating. If you need conformal coating for harsh environments, look for a suffix with a “G” (e.g., DS3800HFPG1G1G). The standard HFPG is suitable for indoor environments. If your plant has high humidity or corrosive conditions, consider a coated variant.

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