This Product Selection Guide contains information to help select products in the Interlock Switches category on DigiKey.com
Interlock switches, or safety interlock switches, are used to prevent a machine from operating in unsafe conditions.
SelectionCharacteristics
Type: Refers to the various categories or classifications of switches available.
Circuit: Describes device function in terms of a number of poles and throws, as is typical for mechanical switches. For more information please see: Switch Basics, Examples of Pole and Throw
Current Rating (Amps): Typically this represents the maximum current to which a device will meet its given specifications. Exceeding this current may damage the device and/or other system components.
Voltage Rating: Typically this represents the maximum voltage rating to which a device will meet its given specifications. Exceeding this voltage rating may damage the device and other system components.
Voltage - Supply: Typically represented by a range, this indicates the low and high voltage limits which one can expect standard operation. Voltages outside this range may damage the device and other system components.
Holding Force: Indicates the amount of force or pressure that is required to keep the switch in its actuated or locked position.
Actuator Type: The specific design or style of the mechanism used to change the switch position.
Termination Style: Selection of termination style used to connect the device to a system, such as cable leads, screw terminal, or wire leads.
Features: These are different capabilities or properties of the device such as automatic reset or manual override.
Must Operate: The maximum applied field strength (minimum separation distance with a specified actuator) required to actuate a magnetic sensor.
Must Release: The minimum applied magnetic field strength (maximum separation distance with a specified actuator) at which an a sensor must return to an inactive state.
Conduit Thread Size: Indicates the diameter and thread type of the conduit opening that is compatible with the interlock switch.
Operating Temperature: Recommended operating temperature, typically given in a range or as a maximum. Exceeding these temperatures may affect performance or damage the device and other system components.
Ingress Protection: IP (Ingress Protection) Ratings (IP20, IP65, IP67 etc.) - Define how likely it is that water and dirt will get into the system. The first number is for dirt and solid contaminants and the second number is for water.
IP Ratings
| Protection Level | Solids | Liquids |
|---|---|---|
| 1 | Protected against solids larger than 50mm. | Protected against vertically falling drops of water. Limited Ingress permitted. |
| 2 | Protected against solids larger than 12.5mm. | Protected against vertically falling drops of water with the enclosure tilted up to 15 degrees from vertical. Limited ingress permitted. |
| 3 | Protected against solids larger than 2.5mm. | Protected against spraying water up to 60 degrees from vertical. Limited ingress permitted for 3 minutes. |
| 4 | Protected against solids larger than 1mm. | Protected against water splashed from any direction. Limited ingress permitted. |
| 5 | Protected against dust. Limited ingress of dust permitted. | Will not affect operation of equipment 2-8 hours. Protected against jets of water. Limited ingress permitted. |
| 6 | Dust tight. No ingress of dust 2-8 hours. | Protected against powerful jets of water. Limited ingress permitted. |
| 7 | ______________________ | Protected against the effects of immersion in 15cm-1m for 30 minutes. |
| 8 | ______________________ | Continuous immersion in water up to 3m for long periods of time. |
| 9 | ______________________ | Protected against high pressure jets of hot water. (30 seconds) |
| 9K | ______________________ | Protected against high pressure jets of hot water. (2 minutes) |
Approval Agency: An indication that the product meets the minimum safety standards of an approving agency. These agencies are either government entities or private third-party labs that protect consumer safety.
ProductExamples
| MFR PART # | D40A-1C5 |
|---|---|
| DIGIKEY PART # | SW1454-ND |
| MANUFACTURER | Omron Automation and Safety |
| DESCRIPTION | SENSOR HALL DIGITAL WIRE LEADS |
| DATASHEET | Click Here |
| MFR PART # | SI-RFPT-HP5 |
|---|---|
| DIGIKEY PART # | 2170-SI-RFPT-HP5-ND |
| MANUFACTURER | Banner Engineering Corporation |
| DESCRIPTION | SI-RF SAFETY SW HIGH CODE AUTO |
| DATASHEET | Click Here |
| MFR PART # | D4NH-9BBC |
|---|---|
| DIGIKEY PART # | Z7335-ND |
| MANUFACTURER | Omron Automation and Safety |
| DESCRIPTION | SWITCH SNAP ACT DPST-NC 10A 120V |
| DATASHEET | Click Here |
MediaLinks
Videos
Animation for Interlock Door Switches with Solenoid for D4NSL-N / D4NL / D4JL
KS2D Interlock door switch
Articles
Rating and Specifying Safety Interlocks
Safety-Circuit Basics for Design Engineers
Satisfying Functional Safety Standards
Product Training Modules
Electronic Component Information and Resources
TechForum
TechForum posts on Interlock Switches