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Solenoid Controlled Interlock Switches

Particular types of machinery within certain automation safety applications require a 'run-down' time before all of the machine's moving parts have come to a controlled rest so that they no longer pose a risk to plant personnel. In these scenarios, the machine's guard doors must be held closed until the machine's run-down time has expired. 

Similarly, initiating a safety-related stop function on a machine before its cycle-time has concluded can cause operational issues and disrupt production. A machine that is interrupted mid-cycle, such as arc-welding robots, can take a significant amount of time to restart as these machines may need to be reprogrammed before the fault state can be cleared. To overcome this, the safety interlocking system should hold the door closed until the machine has finished its current operating cycle, before entering a safe state of operation. 

One method of preventing premature access is to use interlocking devices with guard locking functionality. Within Trapped Key interlocking systems, this means using a solenoid controlled key switch whereby operators must request entry into the machine, typically using a local push button. The trapped key is only released once the machine has entered a safe state of operation and a signal has been sent to 'energise' the solenoid that is holding the key in place. 

SS Solenoid Controlled Key Switch

The 'SS' solenoid controled key switch is a trapped key interlocking device for use in guard locking applications whereby the removal of the key can only be achieved once the machine's run-down time has expired and the solenoid has been energised, and subsequently released. This safety interlock switch can either be mounted in a machine's control panel (SS-B) or can be supplied in a polycarbonate enclosure (SS-F). 

This switch can be fitted with a standard stainless steel dustcover or a padlockable variant to protect against dust ingress. 

  • No. of Locks: 1>>8
  • Switch Current: 20A/32A/63A
  • Solenoid Voltage: 24V DC /110V AC/ 110V DC
  • Switch Contacts: 4NO/0NC or 2NO/2NC
  • Enclosure IP Rating: IP66
  • Minimum Operating Current: 5mA at 20v

Check the Specs

For more information on these products, download the technical datasheets using the following link to view the products technical specification, safety related data, dimensional drawings and best practice in terms of installation and maintenance.  

MSS1-WP Mini Solenoid Controlled Key Switch (Weatherproof)

The MSS1-WP is a miniature version of the solenoid controlled trapped key interlock switch that can be mounted in a machine's control panel with limited space availability. It has been specifically designed to fit within a 65mm (W) x 95mm (L) x 55mm (H) space envelope. 

The unit has an IP rating of IP66, making it a weatherproof switch for use in outdoor applications. For further protection, the unit is supplied with a stainless steel dustcover as standard but can also be supplied with padlockable variant to protect against dust ingress. 

  • Solenoid Voltage: 24V DC/48V DC/110V (AC/DC)/230V (AC/DC)
  • Minimum Operating Current: 5mA at 20v
  • 2NC 3A Key monitoring contacts 
  • 2NC 3A Solenoid monitoring contacts 

Check the Specs

For more information on these products, download the technical datasheets using the following link to view the products technical specification, safety related data, dimensional drawings and best practice in terms of installation and maintenance.  

MSSR Miniature Enclosed Solenoid Controlled Key Switch

The MSSR is a miniature solenoid controlled trapped key interlock switch that is supplied within a Metal IP66 enclosure. The enclosure also includes a single green push button that acts as a 'START/STOP' function.

In normal operating circumstances, an operator must 'request entry' using the push button which brings the machine to a controlled stop after its rundown time has subsided. Only then can the solenoid be energised, allowing the removal of the trapped key. 

  • Solenoid Voltage: 24V DC only
  • Minimum Operating Current: 5mA at 20v
  • 2NC 3A Key monitoring contacts 
  • 2NC 3A Solenoid monitoring contacts 

Check the Specs

For more information on these products, download the technical datasheets using the following link to view the products technical specification, safety related data, dimensional drawings and best practice in terms of installation and maintenance.  

Still unsure on safety?

If you are currently working on a machiney safety project and are unsure of the best way of safeguarding your machine, we can help you to specify the appropriate safety device based upon your application. 

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