Unit installation

13
…always there
Mains Fail
If an AC fail signal is provided from the power supply, this can be connected to
one of the pin alarm input terminals. For 11 Zone STU connect this to TB1-12,
in this case the AC fail alarm will not be indicated on the STU status LED.
Tamper
If a tamper signal is provided this can be connected to one of the pin alarm input
terminals. The tamper alarm can also be generated and sent to the ARC if the
STU itself detects a tamper, such as the removal of the NVM.
Power Connection
As stated at the beginning of the Installation section, the power supply must
be totally powered down (switch off mains and disconnect the battery) before
making these connections.
For 3GSTU-12V units, connect a 12 V DC power supply to TB3. Connect +12V to
the terminal labelled V+ and 0V to the terminal labelled 0V.
For 3GSTU-24V and fire stu units, connect a 24 V DC power supply to TB3.
Connect +24V to the terminal labelled V+ and 0V to the terminal labelled 0V.
If the STU is to be powered from a separate power supply, the “0V” terminal on
TB3 must be connected to the alarm panel common (0V) and the PSU 0V.
For 3GSTU-PLI units, power supply connections are made automatically when it is
plugged in to the host alarm panel.