Invensys Triconex 3623 16-Ch Supervised DO 120VDC

Product Overview

The 3623 is a 16-channel supervised TMR digital output module manufactured by Invensys Triconex for the Tricon safety instrumented system. Operating at 120 VDC, it drives safety-critical field devices such as solenoid valves, motor starters, and shutdown relays with voltage loopback verification on each channel. The module's supervised output circuitry independently verifies the operation of each output switch, detecting latent faults and wiring failures without requiring actual process actuation.

Key Specifications

• System: Invensys Triconex Tricon SIS
• Type: TMR Supervised Digital Output
• Channels: 16 outputs, commoned
• Nominal Voltage: 120 VDC
• Voltage Range: 90–150 VDC
• Maximum Voltage: 160 VDC
• Voltage Drop: < 1.5 VDC typical
• Current Rating: 0.8 A per point, 4 A surge per 10 ms
• Minimum Required Load: 30 mA
• Load Leakage: 4 mA maximum
• Fuses (Field Termination): 1 A fast-acting per output
• Point Isolation: 1500 VDC / 2500 VDC
• Power Module Load: < 10 watts
• Diagnostic Indicators: PASS, FAULT, ACTIVE, LOAD/FUSE per point

Features & Benefits

1. Supervised Loopback Verification: Voltage loopback circuits verify each output switch independently of load presence, catching latent faults before they impact safety.
2. Quadruplicated Voter Circuitry: Four redundant voter paths process TMR output commands, guaranteeing correct field state even with multiple internal faults.
3. High-Voltage DC Drive: 120 VDC output with 0.8 A continuous and 4 A surge capability drives large inductive loads directly.
4. Per-Point Fuse Protection: Individual 1 A fast-acting fuses on the ETP isolate short-circuit faults to a single channel.
5. Hot-Spare Support: Enables online replacement of a failed module by a spare without interrupting the safety function.

FAQ

Q: What is the difference between 3623 and 3624?
A: The 3623 is a 120 VDC supervised TMR DO with 16 commoned outputs. The 3624 is a 24 VDC opto-isolated commoned supervised TMR DO for lower voltage applications.

Q: What does the LOAD/FUSE alarm indicate?
A> The LOAD/FUSE indicator activates when the detected field voltage does not match the commanded output state, signaling an open load, blown fuse, or wiring fault.

Q: Can the 3623 be mixed with 3625 in the same chassis?
A> Yes, different Tricon output modules can coexist in the same chassis provided each is installed in its correctly keyed slot and the ETP is matched to the module type.

Installation Guide

• Install the module into a Tricon digital output slot in the chassis.
• Connect 120 VDC field power to the external termination panel (ETP).
• Wire each output to the field device coil with proper polarity for DC loads.
• Install 1 A fast-acting fuses on each ETP output circuit.
• Install freewheeling diodes across all inductive DC loads to protect output switches.
• Verify loopback diagnostics by commanding each output ON and OFF while monitoring the LOAD/FUSE indicator.

Selection Tips

• Voltage Standard: The 3623 is rated for 120 VDC. For 24 VDC safety outputs, select the 3624 or 3604E.
• Load Verification: Ensure each field device draws at least 30 mA for reliable loopback detection. Add a parallel resistor if necessary.
• Inductive Protection: Specify fast-recovery freewheeling diodes rated for the 120 VDC coil voltage and surge current.
• ETP Matching: Use an ETP designed for 120 VDC supervised outputs with individual fuse positions.