The actual volume flow is recorded using a membrane pressure transmitter by means of the differential pressure method. For long-term stabilisation of the measurement, the standard scope of delivery includes an automatic zero-point compensation procedure. This ensures that the measurements will be continued to be exact, even at low differential pressures.
The measured volume flows are evaluated and, in accordance with the control algorithm, cause the damper in the volume flow controller to be adjusted by the connected continuous actuator. The controller acts rapidly and stably, and the response time is less than 3 seconds. At fume hoods, the current operating state is indicated on a control panel.

The exchange of actual volume flow values with other systems only takes place via analogue 0-10 V signals.

To meet all the demand placed on a variable and diverse control mechanism, the system is equipped with numerous configurable I/O interfaces.

• Integrated membrane pressure transmitter with zeroing valve
  for long-term stabilisation of the measurement



• 3 Digital inputs for potential-free contacts, e.g. for
  - Switching between types of operation day / night operation / full shut-off
  - Integration of a contact for window opening 500 mm as per DIN 14175
  - Integration of a motion sensor



• 5 Digital outputs as switching contacts (4 closer relays, 1 changeover relay)
  - Changeover contacts, e.g. alarm forwarding to building management systems
  - Make contacts, e.g. for light control, window closing unit



• 7 Analogue inputs for 0-10 V or 2-10 V signals
  - TCU-II usage fume hood controller:
  one input is occupied by velocity sensor
  remaining inputs can be used for summation of volume flows
  - TCU-II usage pressure controller:
  one input is occupied by the pressure transmitter



• 4 Analogue outputs for 0-10 V or 2-10 V signals
  - 1 analogue output is occupied by the actuator of the controller
  - 3 analog outputs, e.g. for actual volume flow values



• Socket for standard control panel or expanded control panel AF-1



• Socket for service/configuration PC
  for configuration with LabConnect software and software update



• Supply voltage 24 V AC / DC
  with easy-to-install double terminals