t
a
ms elektronik
GBM-8.2
2.2. Use in digital systems
The GBM-8.2 can be used independently of the digital format with which the layout is
controlled. A typical application in digital systems is the combination with feedback modules
that read in ground contacts (e.g. s88 feedback modules). The eight outputs of the GBM-8.2
are arranged in such a way that they can be directly connected to the inputs of the s88
feedback modules from the Tams Elektronik product range (e.g. S88-3** or S88-6**).
In digital systems, a high sensitivity of the occupancy sensor can become a problem if
interference voltages from the digital system cause false alarms. With the GBM 8.2, the
sensitivity can be set separately for each track section at a trim potentiometer so that
interference from the digital system has no influence on the busy signals.
The inputs and outputs of the GBM-8.2 are galvanically separated from each other by
optocouplers. This filters out interference peaks and effectively prevents ground loops ("hum
loops") and fault currents.
Info: Galvanic isolation
In digital layouts, the circuits for
supplying the tracks and the
digital devices can either be
galvanically (i.e. electrically)
separated from each other or
connected to a common,
continuous ground. Establishing
a common, continuous ground is
prone to errors in practice and
therefore unreliable, especially in
larger layouts.
With the use of galvanically
separated circuits, ground loops
("hum loops") and fault currents,
which can cause malfunctions
and in the worst case damage to
the digital devices, can be
reliably prevented.
With track occupancy detectors
such as the GBM-8.2, the inputs
(for connecting the monitored
track sections) are galvanically
separated from the outputs (for
connecting digital feedback
devices). The signals (i.e.
occupancy messages) are passed on, but no electrical energy.
Operation overview | 7
Summary of Contents for GBM-8.2
Page 18: ...GBM 8 2 tams elektronik 18...
Page 19: ...tams elektronik GBM 8 2 19...
