Description
GE HE693THM809C
Technical Specifications:
- Channels: 8 RTD inputs
- Types: Pt100, Pt1000, Cu50, Cu100, Ni120
- Wiring: 2-wire, 3-wire, 4-wire supported
- Resolution: 0.01°C
- Accuracy: ±0.15°C (4-wire Pt100)
- Excitation Current: Programmable 0.1–2.0 mA
- Update Rate: 10 Hz
- Isolation: 2000 VDC (enhanced)
- Power: ~4 W
Functional Features:
- Programmable excitation current per channel
- Lead resistance compensation for 2-wire and 3-wire configurations
- Per-channel fault detection (open, short, out-of-range)
- Calibration coefficients stored in non-volatile memory
- LED status per channel pair
Application Scenarios:
- Generator stator winding temperature (critical for insulation life)
- Steam turbine bearing temperature
- Transformer oil and winding temperature
- High-precision process temperature control
Material Composition:
- PCB: 6-layer with precision thin-film resistors for bridge circuit
- Connectors: 4-wire RTD terminal blocks with gold plating
- Enclosure: Sealed aluminum housing for environmental protection
Working Principle: A constant current excitation is applied to the RTD through the configured wires. The voltage drop across the is measured by a precision differential amplifier. The resistance is calculated using Ohm’s law and converted to temperature using the Callendar-Van Dusen equation stored in the module firmware. Installation Requirements:
- Always use 4-wire configuration for highest accuracy
- Keep RTD leads in conduit separate from power cables
- Verify excitation current does not cause self-heating errors
Usage Precautions:
- Do not exceed 2 mA excitation current on Pt100 sensors
- Recalibrate every 2 years or after any module replacement
- Check for ground faults on RTD circuits before commissioning
