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GE DS3800NPSJ1B1B
Product Name: GE Speedtronic Mark VI Extended-Temperature 120 VAC Input Board
Product Introduction: The DS3800NPSJ1B1B is GE’s extreme-environment AC digital input module for the Mark VI Speedtronic system. It combines the fast programmable filter from the 1A1A variant with extended-temperature components from the 1B1B design. Released in 2017 for extreme-climate turbine applications, it is the board to install when the ambient is outside the comfort zone of standard NPSJ boards.
Detailed content
Technical Specifications:
- Number of Inputs: 16 digital inputs, optically isolated per channel
- Input Voltage: 120 VAC ±10% (108–132 VAC)
- AC Frequency Range: 47 to 63 Hz
- Input Threshold (ON): > 70 VAC at 25 °C, derates to > 75 VAC at 70 °C
- Input Threshold (OFF): < 25 VAC at 25 °C, < 30 VAC at 70 °C
- Input Current: 5 mA typical at 120 VAC (stable across temperature range)
- Input Impedance: 24 kΩ (temperature-compensated)
- Input Filter: Programmable 1 ms to 50 ms per channel (VME-configurable)
- Minimum Detectable Pulse: 1.2 ms (filter at 1 ms, 25 °C)
- Zero-Crossing Detection: Fast response, < 200 µs delay, temperature-compensated
- Isolation Voltage: 1.5 kV channel-to-ground and channel-to-channel
- Host Interface: VMEbus P1 connector, A24/D16 addressing, single 16-bit register
- VME Mapping: 0xD000
- Power Draw: 5 VDC @ 0.68 A typical
- Operating Temperature: -40 to +70 °C (ambient)—extended range
- Storage Temperature: -55 to +100 °C
- Dimensions: 6U VME (233 mm × 160 mm)
- Field Connector: One 64-pin D-Sub female (P2)
- Firmware Version: v1.1B (temperature compensation, programmable filtering)
Functional Features:
- Sixteen 120 VAC inputs, each optically isolated, with a programmable filter from 1 ms to 50 ms.
- Temperature-compensated thresholds and impedance hold the ON/OFF points stable from -40 °C to +70 °C.
- Fast zero-crossing detection responds in under 200 µs.
- Firmware v1.1B includes temperature compensation to keep thresholds stable across the entire operating range.
- Slightly higher power draw (3.4 W from the 5 V rail) due to the extended-temperature component selection.
Application Scenarios:
Desert plant control rooms hitting 65 °C summer ambient; cold-climate turbine installations down to -40 °C; any Mark VI Speedtronic application where standard NPSJ boards throw false inputs due to optocoupler drift at temperature extremes.
Structural Characteristics:
Standard 6U VME form factor. The P1 connector interfaces to the VMEbus; the P2 64-pin D-Sub female connector brings out the 16 field input channels. Optocouplers, resistors, and capacitors are all selected for -40 to +70 °C operation with tighter thermal derating curves than the standard NPSJ.
Working Principle:
Each 120 VAC field input passes through a temperature-compensated 24 kΩ input impedance, a programmable 1–50 ms filter, and a fast zero-crossing detector (response < 200 µs). The conditioned signal is opto-isolated at 1.5 kV and presented to the VMEbus as a single 16-bit register mapped at address 0xD000 (A24/D16). Firmware v1.1B continuously compensates threshold points against die temperature.
Installation Requirements:
Insert the board into a Mark VI VME rack, ensuring the P1 connector seats fully in the VMEbus backplane. Field wiring terminates at the 64-pin P2 D-Sub female connector. Configure per-channel filter timing (1–50 ms) via VME registers. The board draws 0.68 A from the 5 V rail—verify backplane PSU headroom.
Usage Precautions:
Genuine 1B1B boards require testing at both -40 °C and +70 °C to verify the programmable filter and zero-crossing detection. Maintain input voltage within 108–132 VAC; sustained over-voltage accelerates optocoupler aging. Because the board maps to a fixed VME address (0xD000), confirm no other board in the rack uses the same address. Periodically re-verify the 1.2 ms minimum detectable pulse at the 1 ms filter setting to confirm component health.
