Bridge hardware settings

Fabman bridges can be tightly integrated with your machines to allow detailed monitoring and enable additional safety features. Have a look at the bridge connection scheme for technical instructions on connecting inputs and outputs to a bridge.

Attention: Opening a bridge’s enclosure or connecting any equipment to Fabman must be performed by a qualified electrician! Fabman GmbH cannot be held responsible for any damage caused by improper use of or tampering with electrical equipment.

Control settings

First, you need to select whether your bridge controls …

  • a machine or power tool,
  • an electric door lock – for example the main entrance, a meeting room door, or access to the storage room – or,
  • nothing. In that case, you can use it as a Check-In/Check-Out-Terminal to track people’s time in the lab.

All subsequent options depend on this setting.


You can connect various signals to the bridge’s "Input 1", "Input 2" and "AC Input" ports. Fabman currently understand the following signals:

  • Busy/Idle status: Let Fabman distinguish whether a machine is currently idle or active (eg. milling spindle is active, laser is active, or filament is being extruded). See Equipment: idle and busy states for details.
  • Exhaust filter status: Many air filter systems (eg. for laser cutter exhausts) offer a status signal that indicates whether the filter is operating normally. Connect this to Fabman to automatically shut down equipment when the filter fails and keep track of when and where those issues arise:
  • Safety enclosure / safety mat: Prevent users from switching on equipment while they don’t adhere to safety precautions and remind them with a helpful message.
  • Open once: (Doors only.) Allows you to connect an external switch to open the door. When the input is triggered, Fabman opens the door as if someone had swiped their card or used the QR code.
  • Toggle "keep open": (Doors only.) Can be used together with the auxiliary relay’s "keep open" signal setting to tell an electric door lock to stay open, eg., to keep a door unlocked during opening hours. (If your door lock supports such a "always open" signal.) Triggering this input once changes auxiliary relay to on. Triggering it again changes the relay back to off

Auxiliary Relay

You can use the bridge’s auxiliary relay to control additional equipment. There are several options available:

  • Mirror primary relay: The auxiliary relay is switched on whenever the primary relay is. You can use this, eg., to automatically turn on an exhaust air filter when the equipment is turned on.
  • Switch on when busy: The auxiliary relay is switched on whenever the primary equipment is busy and switched off while it is idle or off.
  • Light: Like "mirror primary relay", but the relay is switched on and off in sync with the bridge’s warning LED. This can be handy if the warning LED is not visibly from the default working position: Connect the auxiliary relay to a workbench lamp or the machine’s lighting and it starts blinking when there’s anything that requires the operator’s attention.
  • "Keep open" signal: (Doors only) Is off initially, but can be toggled with a toggle "keep open" input signal. (See above.)

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