ADEMCO 7845CZ Installation And Setup Manual page 25

DC Power Connections and Options
Primary power for the 7845CZ is provided by the auxiliary power output of the control panel
(9.6V -13.8V, typical). See Figure 9.
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When calculating the total load on the auxiliary power output of the control panel, 100mA
must be budgeted for the 7845CZ. Under normal operating conditions, the 7845CZ will not
pull more than 100mA.; however, it will draw 400mA during a transmission. The excess
energy is extracted from the K4362 battery. If the battery fails, however, the excess current
is drawn from the control panel. If drawing 400mA from the control panel for 3 seconds
presents a problem, then the response to the current limit question should be YES when the
unit is programmed. The disadvantage to this selection is that the radio will not transmit
when the battery fails. If it is possible to budget 400mA to the 7845CZ or if drawing that
amount of current for 3 seconds is not a problem, then the response to the current limit
question should be NO. The 7845CZ is defaulted to no current limit.
Another method of powering the 7845CZ is with a wall mounted DC power supply: ADEMCO
p/n 7720V2TR (or 7720V2TR-CN for Canada). Because there is no backup power in this
configuration, the K4362 battery must be used. Additionally, the 7845CZ must be grounded
to the control panel as shown in Figure 10.
12V AUX
GND
CONTROL PANEL
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BATTERY
ADEMCO
K4362
12V AUX
GND
CONTROL PANEL
ADEMCO
7720V2TR
12.5V
300mA
(-) (+)
NC
Section 4: Installation and Setup
P1 BATT
TB1
V+
GND
7845CZ
BATTERY
ADEMCO
K4362
P1 BATT
TB1
V+
GND
7845CZ
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