User Manual

SGD-SB2025NT-TUM, Part 2
Jan 12 Page 46 SOLAR COMMISSIONING
Figure 38. NI Engineering – Signalling page.
5.2.2.1 Signalling In
The signalling input may take the form of a variable voltage or tone. The NI will automatically
determine the meaning of this input according to the mode of operation, i.e. Central or Station,
although setting to ‘Voltage’ has no meaning for an NI operating in Central mode. The type of
signalling required is selected from the drop-down list as shown in Figure 39 .
Figure 39. Signalling In – Menu Options.
If a voltage input is used, it must be wired to the dedicated input on the NI Facilities connector (see
Table 7 ). A signalling tone must be applied to the composite audio input.
Note.
On a P25 system, the Signalling tab of the NI Engineering window differs only in that
the ‘Signalling In’ box is always set to ‘Voltage’ mode because there is no tone RSSI
available from the SB2025 in P25 mode.
5.2.2.1.1 Voltage
Voltage I/P used as RSSI in Station Mode.
The voltage input range is from 0 V to +5 V and this is measured and reported as a value from 0 to
1023 respectively. The ‘Boundaries’ boxes (see Figure 40 overleaf) define the maximum and
minimum values, and an input level between these limits will be translated into one of the 14 Solar
internal RSSI levels. An input below the minimum value will be regarded as no signal, whereas an
input greater than the maximum value will continue to be regarded as the top RSSI level. Setting a
minimum value of zero disables the function.
The setup process for the RSSI input levels is as follows: