More Outputs

By connecting expansion relays to a safety relay it is easy to increase the number of safe outputs. This means that an unlimited number of dangerous machine operations and functions can be stopped from one safety relay/PLC.

Safe Soft Stop

When a gate is opened a program stop is first given to the machine’s PLC/servo which brakes the dangerous operations in a soft and controlled way. The safety outputs then break the power to the motors, that is, when the machine has already stopped. Normally between 0.5 and 1 second is needed to brake a dangerous machine operation softly.

Soft stop ensures many advantages:

• The machine lasts longer.
• Parts being processed are not damaged.
• Restart from stopped position is enabled and simplified.

A safe soft stop is achieved by means of a safety relay which gives the program stop, and an expansion relay, E1T, which gives safe delayed stop signals. See chapter “Connection Examples”. The drop time delay on a E1T can as standard be selected from 0 to 3 seconds. By connecting several E1Ts in series even longer times can be achieved.

Safety Level

The E1T has twin stop functions, that is, two relays with mechanically operated contacts. A monitored stop function is achieved by connecting the test output (terminals X1 and X2) to the test or reset input on the safety relay which is being expanded. One condition for a safe delayed stop is that the delay time cannot increase in the event of a fault. The E1T complies with this requirement.

When are delayed safe stops used?

Delayed safety stop signals can be used for emergency stops accordingto EN418 § 4.1.5. Stop category 1 and NFPA 79, i.e. a controlled stop with power to the actuator(s) available to achieve the stop and then removal of power when stop is achieved. Stop category 1 may be permitted when it is not possible to gain physical access to the machine before the safe stop is affected e.g:

• Gates, access time is normally over 1 sec.
• Covers and gates which are locked until dangerous operations and functions have been stopped.
• Long distances between a safety device and a dangerous machine function.

Applications

• More Safety Outputs
• Delayed Safety Outputs
• Output Contact Indication

For further information including technical data and connection examples click here. E1T Expansion Relay

E1T Expansion Relay

If you're using Safety Relays and Expansion Relays, check out the Vital 1 Controller that can monitor up to 30 Safety Devices and the Pluto Safety PLC that can monitor up to 150 Safety Devices.

Features

• Width 22.5 mm
• LED indication of output
• 4 NO relay outputs
• 24 VDC
• Single or dual channel operation option
• Quick release connector blocks

Regulations and Standards

Approvals