I. Model Positioning and Family

4500 = Series designation (including 4501/4502/4503/4504/4505/4506/4507/4508, etc.)

Classification: Tricon / Trident SIS System I/O Layer

Architecture: TMR (Triple Module Redundancy), 2oo3 Voting, No Single Point Failure

Safety Certification: IEC 61508 SIL3, IEC 61511, ATEX Zone 2

Status: Mainstream in service, long-term supply, stable spare parts

II. Core Common Specifications (Universal for All Series)

Redundancy: Triple redundancy for TMR, each channel is independent, and faults can be replaced online

Safety level: SIL3 (the highest industrial safety level)

Backplane: Special redundant backplane for Tricon

Operating temperature: -40 °C ~ +70 °C (wide temperature industrial grade)

Protection: IP20, suitable for cabinet installation

Certifications: CE, UL, ATEX, TUV

Communication: Supports Modbus RTU/TCP, OPC, DNP3, etc.

III. Common Models and Functions (4500 Series Subdivisions)

4500 (Basic type, 16DI + 16DO mixed module)

16 digital inputs (DI) + 16 digital outputs (DO)

DI: 24 VDC, response ≤ 1 ms

DO: Relay (double-pole double-throw), 2 A @ 250 VAC / 30 VDC

Purpose: General switch quantity safety interlock

4501 / 4502 (Pure DI module)

32 digital inputs (24 VDC)

High-density DI, used for a large number of on-site switches, contacts, valve position feedback

4503 / 4504 (Pure DO module)

32 digital outputs (relays / transistors)

Drive solenoid valves, contactors, alarm lights, safety gates

4505 / 4506 (Analog Input AI)

8/16 AI: 4–20 mA, 0–10 V, RTD/TC

Used for process parameter safety monitoring such as pressure, temperature, level, flow, etc.

4507 (Analog Output AO)

8 AO: 4–20 mA / 0–10 V

Safety regulation output, such as emergency valve shut-off, cut-off control

4508 (High-density Mixed I/O)

16DI + 8DO + 4AI + 2AO integrated

Compact system preferred, saves slots and costs

IV. Differences between 4500 and Other Tricon Series

4500 Series: Tricon/Trident universal I/O, SIL3, wide temperature, full redundancy

3500/3600/3700/3800: Older Tricon I/O (3501E DI, 3604E DO, 3721 AI, 3805E AO), gradually replaced by 4500

Tri-GP Series: Economic SIL2/SIL3, fewer I/O points, lower cost

V. Typical Application Scenarios

Oil and Gas: Wellhead ESD, pipeline high/low pressure interlock, safety valve control

Chemical / Petrochemical: Reactor over-temperature / over-pressure protection, F&G system, burner safety interlock

Power: Boiler / turbine protection, generator excitation interlock, high-voltage switch safety control

Pharmaceutical / Fine Chemical: Explosion-proof area safety isolation, inert gas interlock

VI. Selection in One Sentence

4500 = General Mixed I/O

4501 / 4502 = Large number of switch inputs

4503 / 4504 = Large number of switch outputs

4505 / 4506 = Temperature / Pressure / Level Monitoring

4507 = Safety Regulation Output

4508 = Compact Integrated I/O