1. Introduction

• Function: 40‑channel 24 VDC discrete input monitoring (switches, sensors, relay contacts)

• Architecture: TMR (3‑2‑0) + 1oo2D per‑channel voting

• Safety: IEC 61508 SIL 3 / SIL 4 certified

• Coating: Acrylic conformal coating (humidity, dust, chemical resistance)

• Temp Range: –40 °C to +70 °C (vs T8403: 0 °C to +60 °C)

• Channels: 40 × 24 VDC DI

• Isolation: 2500 V DC optical

• SOE: 1 ms resolution

• Hot‑Swap: Yes

2. Key Differences: T8403 vs T8403C

3. Specifications (T8403C)

3.1 Mechanical

• Form Factor: T8000 chassis module, 56 mm wide, 6U

• Dimensions (H×W×D): 255 × 56 × 210 mm

• Weight: 1.2 kg

• Mounting: T8100 / T8400 chassis slots 1–16

• Connectors: Front TB1–TB5 (5 blocks × 8 channels)

• PCB Protection: Acrylic conformal coating (T8403C)

3.2 Electrical

• System Supply: 20–32 V DC (24 V nominal)

• Power Consumption: ≤ 4 W

• Inputs: 40 × 24 VDC digital input

• Logic 1: 18–60 V DC

• Logic 0: <5 V DC

• Input Current: ~5 mA/channel @24 VDC

• Sink/Source: Configurable (NPN/PNP)

• Isolation: 2500 V DC optical (channel–channel, channel–system)

3.3 Functional

• Voting: 1oo2D per channel (triple measurement + comparison)

• SOE Resolution: 1 ms

• Diagnostics:

  • Open‑circuit detection (per channel, 10 kΩ line resistor)

  • Short‑circuit detection (per channel)

  • BIST, fault logging to HMI

• Response Time: ≤ 1.5 ms

• Data Integrity: BER < 10⁻¹²

3.4 Environmental (C‑version critical)

• Operating Temperature: –40 °C to +70 °C

• Storage Temperature: –40 °C to +85 °C

• Humidity: 5–95 % RH, non‑condensing / condensing tolerant

• Altitude: ≤ 2000 m

• Vibration: IEC 60068‑2‑6 (1 g, 10–150 Hz)

• Shock: IEC 60068‑2‑27 (15 g, 11 ms)

3.5 Safety & Certification

• Safety: IEC 61508 SIL 3 / SIL 4

• Certifications: CE, UL, CSA, ATEX II 3G Ex ec IIC T4 Gc, IECEx

• Fault Tolerance: TMR (3‑2‑0), 1oo2D per channel

• PFHd: < 5.0 × 10⁻¹⁰ / h (SIL 4)

4. Front Panel & LEDs

• PWR (Green): On = power OK

• RUN (Green): On = active; flash = init

• FAULT (Red): On = fault; flash = minor fault

• COM (Green): Flash = backplane active

• TB1–TB5: 5 terminal blocks (8 ch each)

• FG: Functional ground

5. Installation & Wiring

• Torque: Terminals 0.5–0.6 Nm; front screws 0.8–1.0 Nm

• Wire: 16–22 AWG stranded

• Line resistors: 10 kΩ for open‑circuit monitoring

• Hot‑swap: Supported (no shutdown)

6. Operation & Diagnostics

• Power‑up: RUN flashes 5–10 s (BIST)

• Normal: PWR/RUN steady green, COM flashing

• Fault: FAULT on = critical; flash = minor

• SOE: 1 ms time‑stamp, stored in system

7. Ordering Information

• T8403: Standard 40‑Ch DI (0 °C … +60 °C)

• T8403C: Conformal coated, –40 °C … +70 °C

• TC‑8403: Terminal block cable kit

• T8100 / T8400: Chassis