D7A-2 Horizontal Vibration Detection Switch – Complete Technical Specifications

1. Product Identification

Product Name: Automatically Small Horizontal Vibration Detection Switch
Type Name:D7A-2
Document Number: No. 1778281-3A1
Issue Date: April 22, 1999
Manufacturer: OMRON Corporation
Drawing Number: DRWG. No. 6421443-2

2. Mechanical Structure & Operating Principle

2.1 Basic Mechanism

• Structure Type: Mechanical contact system that opens/closes via earthquake wave vibration
• Protection Rating: IP40 (protected against solid objects >1mm, no liquid protection)
• Return Mechanism: Automatic return type (self-resetting)

2.2 Sensitivity Specifications

• Set Sensitivity Range: 90–170 cm/s² (Gal)
• Test Method: Horizontal continuous excitation at 0.3, 0.5, and 0.7 cycle/second frequencies
• Operating Threshold: Designed to activate at earthquake wave intensities of 80–250 cm/s²

2.3 Response Times

• Horizontal Return Time: ≤ 20 seconds (time to return to normal state after device is fixed at installation level allowance, at 10°C or higher)
• Circuit Return Time: ≤ 1 minute (time for switch circuit to return to original state after vibration stops)

2.4 Installation Requirements

• Mounting Method: PCB mounting (board thickness: 1.6 mm)
• Installation Level Allowance: ±5 degrees or less from horizontal when installed normally
• Contact Operation: Excites horizontally and turns ON when vibration exceeds set sensitivity threshold

3. Electrical Specifications

3.1 Electrical Ratings

• Voltage: DC 3V
• Current Range: 5 mA to 1 mA (Note: The document shows "DC3V, 5A~DC3V, 1mA" but this appears to be a typo likely meaning 5mA to 1mA based on typical relay/contact specs)

3.2 Electrical Performance

• Contact Resistance: ≤ 1 Ω (initial value)
• Insulation Resistance: ≥ 100 MΩ (measured with DC 250V Megger)Tested between each terminal and earth terminalTested between same-pole terminals
• Dielectric Strength: AC 250V, 50/60 Hz for 1 minuteTested between each terminal and earth terminalTested between same-pole terminals

4. Environmental Operating Conditions

4.1 Operating Environment

• Temperature Range: -10°C to +70°CConditions: No dew formation or freezing permitted
• Humidity Range: 25% to 95% RH

4.2 Storage Environment

• Temperature Range: -30°C to +70°CConditions: No dew formation or freezing permitted
• Humidity Range: 25% to 95% RH

5. Mechanical Durability & Environmental Resistance

5.1 Transportation & Handling Tests

5.2 Environmental Endurance Tests

6. Soldering Specifications

6.1 Dip Soldering

• Maximum Temperature: 270°C
• Maximum Duration: 4 seconds

6.2 Hand Soldering (Iron)

• Temperature: 350°C ±10°C
• Maximum Duration: 3 seconds

7. Performance Criteria Definitions

7.1 "Satisfy Initial Value" Means:

1. Operation Characteristic: Activates at 90–170 cm/s² (0.3, 0.5, and 0.7 cycle seconds)
2. Contact Resistance: ≤ 1 Ω
3. Insulation Resistance: ≥ 100 MΩ
4. Dielectric Strength: Withstands AC 250V, 50/60 Hz for 1 minute

7.2 "No Functional Obstacle" Means:

1. Operation Characteristic: Activates at 80–250 cm/s² (0.3, 0.5, and 0.7 cycle seconds)
2. Contact Resistance: ≤ 100 Ω
3. Insulation Resistance: ≥ 100 MΩ
4. Dielectric Strength: Withstands AC 250V, 50/60 Hz for 1 minute

8. Quality Assurance & Warranty

8.1 Guarantee Terms

• Guarantee Period: 1 year after product delivery
• Scope of Guarantee: Exchange or repair of defective parts caused by manufacturer responsibility
• Exclusions: Labor costs and damage compensation not covered

8.2 Specification Validity

• Valid Period: 1 year from issue date
• Revalidation: Specification becomes invalid if no orders received within 1 year

9. Dimensional Specifications

9.1 Key Dimensions (from drawing 6421443-2)

Overall Dimensions:
- Width: 20.0 ± 0.1 mm
- Depth:  2.0 ± 0.1 mm
- Height: 19.6 ± 0.1 mm

Mounting Hole Spacing: 2 ± 0.1 mm (center-to-center)
PCB Mounting: Designed for 1.6mm thick PCB

9.2 Scale & Tolerances

• Scale: 2:1 (as noted on drawing)
• General Tolerance: ±0.4 mm unless otherwise specified

10. Compliance & Standards

• Ingress Protection: IP40 rated
• Environmental Testing: Per JIS (Japanese Industrial Standards)Salt spray: JIS Z 2371Humidity/heat cycles: Per gas meter regulations
• Quality Management: OMRON inspection regulations for microcomputer components

11. Important Notes

1. Sensitivity Calibration: Factory-set for 90-170 cm/s² operation; designed to detect earthquake vibrations in the 80-250 cm/s² range
2. Installation Critical: Must be mounted within ±5° of level for proper operation
3. Temperature Dependency: Return time specifications are valid at 10°C or higher
4. Maintenance: No user-serviceable components; automatic return mechanism eliminates need for manual reset
5. PCB Design: Ensure 1.6mm PCB thickness for proper mounting and stress relief

12. Manufacturer Information

OMRON Corporation
Corporate Headquarters: Kyoto, Japan
Product Category: Automatic Control Components
Document Control: No. 1778281-3A1 (4-page specification)

Engineering Change History:

• E/C No. A1: Changed to SI units, updated OMRON inspecting regulations for microcomputer (dated 990421)