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3.4.3.2 Pseudo Analogue Input 1 - Supply Volts
Nano_Link
measures the internal battery voltage, and stores it as if it was an additional analogue input. This register
be accessed in two ways:
1.
Using the Alphanumeric Display Module (described in section 10). This scales the register contents and displays
the actual voltage.
2.
By configuring
Nano_Link
as an outstation and interrogating it with a
Micro_Link
base-station. The method of
accessing the register via
Micro_Link
is given in the ‘
Data_Link 2000
Technical Manual’.
The battery voltage can be calculated from the reading using the formula
Battery
=
Value
/
800V
This can be illustrated graphically as follows:
The reading is limited to the range 0…4080, corresponding to a voltage range of 0…5.10V.
Battery-powered units use 3 alkaline batteries giving a nominal 4.5V (i.e. reading of 3600). When they are nearing the
end of their life the voltage drops to 3.65V (corresponding to a reading of 2920). At this point a battery-powered
Nano_Link
will generate a Low Battery alarm.
Mains powered units derive a supply of 5.5V when mains is present, giving a full-scale reading of 4080. If the mains
supply fails the unit continues operating from internal trickle-charged Nickel Cadmium batteries, but the voltage will
drop to about 4.5V (reading 3600). When the batteries are approaching the end of their life the voltage will drop to
4.0V (3200). At this point a mains-powered
Nano_Link
will generate a Low Battery alarm.
3.4.3.3 Pseudo Analogue Input 2 - Radio Received Signal Strength Indicator (RSSI)
If
Nano_Link
uses radio communication, it measures the received signal strength, and stores it as if it was an additional
analogue input. This register be accessed in three ways:
1.
Using the Alphanumeric Display Module (described in section 10). This scales the register contents and displays
the actual RSSI level in dBµV.
2.
By setting a
Nano_Link
base-station to the radio commissioning mode described in Chapter 8.1.2. The value will
then be presented on an analogue output.
3.
By configuring
Nano_Link
as an outstation and interrogating it with a
Micro_Link
base-station. The method of
accessing the register via
Micro_Link
is given in the ‘
Data_Link 2000
Technical Manual’.
The RSSI can be used to deduce the margin by which the path can deteriorate before communication will be lost. RSSI
is measured in dBµV, according to the following formula:
RSSI = Value / 100 - 15 dBµV
0
1
2
3
4
5
0
1000
2000
3000
4000
Value
Battery Volts
Содержание Nano Link IP67
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