RT7 Safety Relay

Connection of Safety Devices

1. Single Channel, 1 NO from +24V

3. Dual Channel, 1 NO, 1 NC from +24V

5. Safety Mat or Contact Strip

The input (contact to S14) must be closed before the outputs can be activated. When the input contact is opened the relay safety output contacts open.

One input contact must be closed (S14) and one opened (S44) before the relay outputs can be activated. The safety relay contacts will open if one or both of the inputs change status or in case of a short-circuit between S14 and S44. Both inputs must return to their initial positions before the relay outputs can be reactivated.

Both 'contact' inputs from a inactivated safety mat/contact strip must be made in order to allow the RT7 relay outputs to be activated. When the safety mat/contact strip is activated or a short-circuit is detected across S14-S23, the relay will de-energize (safety outputs open) and the 'ON' LED will flash. As output S13 has an internal current limit of 60 mA, the RT7 will not be overloaded when the mat/contact strip is activated or a short circuit is detected.

2. Dual Channel, 2 NO from +24V

4. Dual Channel, 1 NO from +24V, 1 NO to 0V

Both input contacts (S14 and S34) must be closed before the relay outputs can be activated. The safety relay contacts will open if one or both of the input contacts are opened. Both the input contacts must be opened and reclosed before the relay can be reset. A short-circuit between inputs S14 and S34 can only be supervised if the device connected to the inputs has short-circuit supervised outputs, e.g. JOKAB JSC light curtains.

Relay functions as option 2, but a short-circuit, in this case between inputs S14 and S24, is supervised (safety outputs are opened).

Reset Connections

Manual Supervised Reset

Automatic Reset

Testing External Contactor Status

The manual supervised reset contact connected to input X1 must be closed and opened in order to activate the relay outputs.

Automatic reset is selected when S53, X1 and X4 are linked. The relay outputs are then activated at the same time as the inputs.

*connected to S13 for safety mat/contact strip

Contactors, relays and valves can be supervised by connecting 'test' contacts between S53 and X1. Both manual supervised and automatic reset can be used.

Output Connections

Relay Outputs

Transistor Outputs

Time Delay Outputs

The RT7 has four (4 NO) safety outputs of which two can be delayed, and 1 NC information output.

In order to protect the RT7 output contacts it is recommended that loads (inductive) are suppressed by fitting correctly chosen VDR's, diodes etc. Diodes are the best arc suppressors, but will increase the switch off time of the load.

The RT7 has three (3) voltage free transistor information outputs.

The transistor outputs are supplied with voltage to Y13 either from S53 (+24V) or externally from 5 to 30 VDC. Y14, Y24 and Y34 follow the inputs and outputs as follows:

• Y14 becomes conductive when the relay input conditions are fulfilled.
• Y24 becomes conductive when both the output relays are activated.
• Y34 becomes conductive when both the delay output relays are activated.

Time delays are selected by linking the appropriate T0, T1 and T2 connections.

When a stop signal is detected a program stop command is first given to the PLC/servo which brakes the dangerous machine operations in a 'soft' and controlled way.

The delayed relay safety outputs will then turn off the power to the motors, i.e. when the machinery has already stopped. It takes usually around 0.5 to 3 seconds for a dangerous action to be stopped softly.