I. Core Parameters (AI3721 / Official Standard Version 3721)

1) Basic Specifications

Model: AI3721 (3721, Differential Analog Input)

Number of Channels: 32 channels / module (differential, point-to-point isolation)

Signal Type (Hardware Jumper + Software Configuration):

Voltage: 0–5VDC, ±5VDC (–5 to +5V)

Resolution: 12 bits / 14 bits (programmable)

Accuracy: ±0.15% FS (0–60°C)

Sampling / Update Rate: 10ms / full channel (high-speed synchronization)

Input Impedance: >10MΩ (differential)

Common Mode Suppression: –85dB (DC–100Hz)

Overload Protection: 150VDC / 115VAC continuous

Isolation: Field ↔ Backplane 1500VAC; Channel-to-channel isolation

Diagnosis: Open Circuit / Short Circuit / Overrange, FVD, Overvoltage Protection

Safety Level: SIL3 (IEC 61508, TÜV Certification)

Redundant Architecture: TMR Triple Redundancy

Power Supply: 24VDC (backplane)

Power Consumption: Approximately 8W

Operating Temperature: –20°C to +60°C

Certifications: CE, UL, CSA, ATEX/IECEx, TÜV SIL3

Installation: Tricon Host Rack Slot (19-inch)

Matching Terminal Board: 9771-210 (16 points) × 2 pieces

Matching Cable: 4000016-015 (flat cable × 2)

2) Panel Indicators (Front Panel of 3721)

PWR (Green): Normal power supply

PASS (Green): TMR decision is normal, module is running normally

FAULT (Red): Module / Channel / Diagnostic Fault

ACTIVE (Yellow): Channel has signal activation

FIELD (Yellow): Field-side fault (open circuit / short circuit)

3) AI3721 vs AI2351 vs AI3351 (Key Differences)

AI3721 (3721): 32 differential, 12/14 bits, 10ms, voltage-specific, isolation, high-speed anti-interference; fast voltage signal (such as strain bridge, high-precision sensor)

AI2351: 8 channels, 24 bits, multiple signals (mA/V/TC/RTD), high precision; critical safety circuits (temperature / pressure / flow)

AI3351: 32 single-ended, 12 bits, 4–20mA/0–5V, high-density economy; large-scale ordinary circuits

II. Usage Instructions (Wiring + Configuration + Maintenance)

1) Wiring (with 9771-210 terminal board, differential)

0–5V / ±5V differential sensor

CHx+ → Signal Positive

CHx- → Signal Negative

SHD → Shielding Layer (single-ended grounding)

Do not directly connect 4–20mA (need to be equipped with I/V converter)

2) Configuration (TriStation)

Select 3721 (AI3721) for hardware slot

Channel Parameters:

Input Range → 0–5V or ±5V

Resolution → 12bit or 14bit

Set filtering, alarm threshold

Download configuration, module restart takes effect

3) Fault Troubleshooting

FAULT + FIELD lights up: Field open circuit / short circuit / overrange → Check wiring, sensor, range

PASS does not light up: Backplane power supply, firmware, TMR synchronization faults

Signal jump: Check shielding grounding, differential line twisted pair, interference source