GE DS3800XTFP

Key Parameters

Temperature Section:

• Input Channels: 8 differential thermocouple/RTD inputs

• Input Types: Thermocouple (J, K, T, E, R, S, B, N), RTD (Pt100, Ni100), millivolt

• Resolution: 16-bit ADC with ±0.05% accuracy

• Cold-Junction Compensation: Built-in per channel

• Diagnostics: Burnout detection, open-circuit detection, over-range/under-range detection

Frequency Section:

• Input Channels: 2 independent counter/frequency channels

• Input Types: Magnetic pickup, proximity, TTL (5V), or 24V DC (jumper-selectable)

• Maximum Input Frequency: 100 kHz

• Measurement Method: Pulse counting or period-averaging (software-selectable)

• Accuracy: ±0.01% of reading

Common Section:

• Isolation: 1500V RMS channel-to-backplane (temperature and frequency sections)

• Temp Range: –30°C to +70°C

• Power Supply: +5V, ±15V from VME backplane

• Physical: 6U VME single-slot board

• Key Features: Combined temperature and frequency measurement, 16-bit ADC, built-in CJC, burnout detection, 100 kHz counter input

Advantages

• Multi-function capability – the DS3800XTFP combines temperature and frequency measurement in a single slot, reducing board count and rack space requirements.

• Built-in cold-junction compensation – on-board CJC for thermocouple inputs eliminates the need for external reference junctions.

• Burnout detection – automatically detects broken thermocouple wires and flags the channel.

• Flexible frequency input – supports both pulse counting and period-averaging measurement modes, accommodating speed and flow applications.

• High accuracy – 16-bit ADC for temperature and ±0.01% for frequency measurement.

• Diagnostic visibility – per-channel LED status and fault detection simplify troubleshooting.

• Drop-in compatible – works with all Mark IV backplanes and processor configurations.

Applications

• Turbine EGT and speed monitoring – measures exhaust gas temperature (EGT) and turbine speed from a single board, ideal for small or modular systems.

• Temperature plus flow – monitors thermocouple or RTD temperatures while simultaneously reading frequency pulses from flowmeters.

• Compact turbine control systems – the General Electric DS3800XTFP is suitable for installations with limited rack slots.

• Bearing temperature and speed monitoring – combines bearing RTD inputs with speed pickup frequency measurements.

• Retrofits – replaces separate temperature and frequency boards with a single, integrated solution.

vs Competitors & Separate Boards

Selection Tips

• Slot-limited installations – choose the DS3800XTFP when you need both temperature and frequency measurement but have limited rack slots.

• Application matching – ensure that the 8 temperature channels and 2 frequency channels meet your system’s requirements. For larger systems, consider separate boards.

• Sensor compatibility – verify that your thermocouple/RTD types and frequency sensors (magnetic, proximity, TTL, 24V) are supported by the General Electric DS3800XTFP.

• Frequency measurement mode – select pulse counting for totalization (flow) or period-averaging for precision speed measurement.

• Spare strategy – keep one DS3800XTFP per 5–8 installed units, especially in compact systems where it serves multiple critical functions.

• Calibration – periodically verify temperature accuracy using a precision calibrator and frequency accuracy using a signal generator.

Critical Precautions

• Thermocouple wiring – use the correct extension-grade thermocouple wire (not copper) for temperature inputs to the DS3800XTFP; incorrect wire types introduce cold-junction errors.

• Thermocouple polarity – observe correct polarity when connecting thermocouples; reversed polarity produces inverted readings.

• RTD wiring – use 3-wire or 4-wire RTD connections to cancel lead resistance; 2-wire connections introduce measurement errors.

• CJC location – the DS3800XTFP cold-junction compensation measures the temperature at the terminal block. Ensure the terminal block is not exposed to drafts or radiant heat.

• Frequency input voltage limits – never apply voltage above 30V to the frequency inputs; magnetic pickups can generate high voltages at high speeds – use appropriate attenuation.

• Cable shielding – use shielded twisted-pair cables for all thermocouple, RTD, and frequency inputs. Ground the shield only at the DS3800XTFP end to prevent ground loops.

• Ground loops – use single-point grounding for all sensors connected to the General Electric DS3800XTFP to avoid ground-loop noise.

• Frequency update rate – when using period-averaging, ensure the update rate is set appropriately for the input frequency; low frequencies require longer averaging.

• Hot-swap – never insert or remove the DS3800XTFP while the rack is powered; this can cause bus errors or component damage.

• ESD handling – always use a grounded wrist strap when handling the DS3800XTFP; CMOS and precision analog components are ESD-sensitive.

• Storage – store spare DS3800XTFP boards in anti-static bags in a dry, temperature-controlled environment.