Status Indicators

Inputs  -  Green LED ON when input is ON

Outputs  -  Green LED ON when input is ON

Reset  -  Yellow LED ON when reset input in ON

EDM -   Yellow LED ON when EDM inputs are ACTIVE

Status - RED LED's ON steady when system is OK

               RED LED's FLASH  ON/OFF when system is in lockout condition

Wiring Information

Terminals A1 and A2 – Power supply input - Connect a suitably stabilized 24V DC power supply
to terminals A1 = +24V DC and A2 = 0V DC. The current consumption of the MFU with no load
applied on the output switching terminals is 150mA.

Terminals A3 and A4 – External device monitor (EDM) - Normally closed switch contacts, in
series from the external power switching devices are connected across terminals A3 and A4. The monitoring circuit checks that the power switching devices both de-energize at the same time the
MFU safety output switches de-energize. If one or both of the power switching devices fail to de-energize at this time the MFU goes into a lockout condition, turning all output switches off.

To reset from as lockout condition it is necessary to remove the 24V DC supply from the MFU and then re-apply.

If the EDM circuit is not used it is necessary to link terminals A3 & A4 otherwise the system will go into a lockout condition at eh next demand upon the safety system.

Terminals A5 and A6 – Safety output 1 switch contact - Connect terminals A5 and A6 to one channel of a machine’s stop circuitry. For example, via an external power-switching relay or directly
 to a safe PLC input or a machines final control element.

Terminals A7 and A8 – Safety output 2 switch contact - Connect terminals A7 and A8 to one channel of a machine’s stop circuitry. For example, via an external power-switching relay or directly
to a safe PLC input or a machines final control element.

If a single channel safety circuit is used link terminals A6 & A7. Terminals A5 & A8 are then connected to the machine's safety circuit. Connecting in this way links safety output switch 1 and safety output switch 2 in a series configuration.

Terminal A9- No Connection

Terminal A10 – Auxiliary electronic switching output 1 - The Auxiliary switching output should
only be used for non-safety critical application. For example connecting an indicator lamp or as feedback to a PLC to confirm the safety outputs have de-energies.

The auxiliary output energizes when safety output switches 1 and 2 energize and de-energizes when the safety outputs de-energize. Auxiliary output ON = 24V DC and OFF- 0V DC.

Terminal A11 – Auxiliary electronic switch – mute out.- The Auxiliary switching circuit energizes when the light curtain is muted, e.g. when suitable signals have been applied to terminals B2 and B3. The output switch is normally used for connecting an indicator lamp or as feedback to a PLC to confirm safety light curtain inputs at terminals B1 and B2 are overridden e.g. in a muted condition.

Terminal A12 – Reset - A suitable switch should be connected between terminal A12 and the 24V
DC supply. If the safety output relays de-energize a depression of the switch is required to
re-energize the output switches to an ON condition.

The MFU's safety output switches will only re-energize when the reset switch is depressed and the released.

Terminal B1 and B2 – light curtain inputs (OSSD1 and OSSD2) - Connect the electronic output switches (OSSD1 and OSSD2) of a light curtain to terminals B1 and B2 respectively.

Note: An internal circuit monitors disparity between the two input channels. If the inputs do not switch together (within 500ms of each other) the system will go into a lockout condition.

Important: If terminal B1/B2 are not used it is necessary to link them to the 24V DC supply. If not
the MFU’s output switches will not energize.

Note: An internal circuit monitors disparity between the two mute input channels. If the inputs do
 not switch within 10 seconds. of each other the system will go into a lockout condition.

Terminal B3 and B4 – mute input signals - Connect suitable mute initiating signals to terminals B3 and B4 respectively. The mute signals override the light curtains operation therefore, the inputs
should only be active during safe periods of the machinery’s operating cycle.

Note: An internal circuit monitors disparity between the two mute input channels. If the inputs do not switch within  10 seconds  of each other the system will go into  a lockout condition.

Terminals B5/B6 and B7/B8 – dual channel emergency stop circuit - Connect one channel of
the machines emergency stop circuit between terminals B5 and B6 and the second channel between terminals B7 and B8. 

An internal circuit monitors for short circuits and switching disparity between the two input channels. If the inputs do not switch together (within 100ms of each other) the system will go into a lockout condition. This configuration meets the the requirements for 'control reliability' and cannot be used in a single channel configuration.

Important, if the emergency stop inputs are not used; it is necessary to link terminals B5 to B6 and terminals B7 to B8.If not the safety output switches will not energize.

Terminals B9 and B11 – 24V DC supply - Additional + 24V DC outputs for connecting to the light curtains etc.

Terminals B10 and B12 – 0V DC supply - Additional 0V DC outputs for connecting to the light curtains etc.