Honeywell 621-9934 (6219934) Product Description

621-9934 (6219934) is the I/O rack power module of the Honeywell 621 series, providing stable direct current power supply for DCS systems such as UCN, IPC 620/621, TDC 3000, and TPS. It is a standard single-slot design and is suitable for medium and low-power I/O racks. 621-9934C is its enhanced version (currently in production). 

I. Basic Information

Brand: Honeywell (Honeywell / ISSC)

Full Model: 621-9934 (6219934)

Series: 621 Series I/O Rack Power Supply

Type: Single-slot Rack-mounted Switching Power Supply Module

Production Status: 621-9934: Obsolete; 621-9934C: In Production

Weight: Approximately 1.45 kg

Dimensions: Approximately 264 × 127 × 32 mm (Standard Width of Single Slot)

Installation: Plug-in into the dedicated power slot of the 621 Series I/O Rack

Common Suffixes:

621-9934C: Enhanced Upgrade Version (Higher Efficiency, Longer Lifespan, More Stable Output)

621-9934-RP: Refurbished / Repaired Version

II. Core Functions

Multiple Stable Outputs: Provide +5V, ±15V three standard industrial voltages

Wide Voltage Adaptive: Automatically recognizes 115/230V AC, universal for global power grids

Comprehensive Protection: Overvoltage (OVP), Overcurrent (OCP), Short Circuit (SCP), Overheat (OTP), Surge Protection

Hot Swap Compatibility: Supports online replacement without interrupting system operation

Redundancy Support: Can be combined with 621-9932 redundant module to build a 1+1 highly reliable redundant system

Status Visualization: LED real-time indication, supports remote system diagnosis

Industrial-grade Reliability: No fan, natural air cooling, suitable for harsh industrial environments

III. Electrical Specifications (621-9934C)

Input Voltage: 115/230V AC (±15%), 47–63 Hz (Automatic Switching)

Input Current: 1.6A @ 115V AC; 0.8A @ 230V AC

Output 1 (Digital): +5V DC / 10A (Maximum)

Output 2 (Positive Analog): +15V DC / 1A (Maximum)

Output 3 (Negative Analog): -15V DC / 1A (Maximum)

Output Precision: ±1% (Full Load, Full Temperature Range)

Ripple Noise: < 50mV p-p (5V); < 100mV p-p (±15V)

Efficiency: ≥ 88% (Typical Load)

Isolation Voltage: 2500V AC RMS (Input - Output - Ground)

Cooling Method: Natural Air Cooling (No Fan)

Built-in Fuse: 900210 (1.60SB @ 115V / 0.80SB @ 230V)

IV. Environmental Parameters

Operating Temperature: 0°C ~ +60°C

Storage Temperature: -40°C ~ +85°C

Humidity: 5–95% RH (No Condensation)

Vibration Resistance: 5–500 Hz, 2 g (IEC 60068-2-6)

Impact Resistance: 15 g, 11 ms (IEC 60068-2-27)

Protection: IP20 (Installed in Cabinet)

Certifications: CE, UL, CSA, 94V-0 Flame Retardant

V. Status Indication (LED)

PWR (Green): Input Normal, Module Operating

5V (Green): +5V Output Normal

+15V (Green): +15V Output Normal

-15V (Green): -15V Output Normal

FAULT (Red): Output Fault / Protection Trigger

OVERTEMP (Yellow): Overheating Warning

VI. Typical Applications

UCN General Control Network I/O Station Main Power Supply

IPC 620/621 System Standard I/O Rack Power Supply

TDC 3000 / TPS System Low-Power Circuits

Analog (AI/AO) + Digital (DI/DO) Mixed Rack Conventional control loops in chemical engineering, power generation, and metallurgy

Old system 621-9931 power upgrade replacement

VII. Model Comparison (621 Series Power Supply) Table

Parameters 621-9934C 621-9931 621-9933

Output +5V/10A; ±15V/1A +5V/8A; ±15V/0.6A +5V/15A; +15V/2A

Width Single slot Single slot Dual slot

Status In production Out of production Out of production

Redundancy Supported (requires 9932) Supported Supported

Hot pluggable Supported Supported Supported

Advantages Performance balanced, in production, high reliability Classic basic model Extra high power

VIII. Common Faults and Troubleshooting

FAULT Red light constantly on

Reason: Output overload / short circuit, internal protection, high temperature

Troubleshooting: Disconnect load → Reset power supply → Check cooling → Replace module

One of the output channels does not light up (e.g. -15V)

Reason: Corresponding circuit overload, analog module failure, internal voltage regulation damage

Troubleshooting: Remove corresponding load → Reset → Replace faulty I/O module → Replace power supply

Input normal but no output

Reason: Input fuse blown, backplane contact不良， internal circuit failure

Troubleshooting： Check built-in fuse → Reinsert module tightly → Replace power supply

IX. Related Models

Upgrade replacement model： 621-9934C (preferred recommendation)

Redundancy management module： 621-9932

Standard low-power power supply： 621-9931

High-power dual-slot power supply： 621-9933

I/O rack： 621-7000 (14 slots)， 621-7010 (10 slots)