Electronics International VA-1A - Manual (Page 6)

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Operating Instructions Operating Instructions Operating Instructions Operating Instructions Operating Instructions Features Features Features Features Features
4. Digital Display: 4. Digital Display: 4. Digital Display: 4. Digital Display: 4. Digital Display:
The VA-1A comes with 12 and 24 volt digital display back light control lines. The digital display should be
backlit all the time. This will allow it to be viewed easily in dim light. The digital display is best viewed in
high ambient light or direct sunlight.
Voltage will be displayed in .1 volt increments and a “V” annunciator will show in the display. Amperage
will be displayed in .1 amp increments for the VA-1A and any external shunted unit 60 amps and below (i.e.,
VA-1A-60 and below). For any external shunted unit above 60 amps (VA-1A-70 and above) amperage will
be displayed in 1 amp increments. Any time the Mode Switch is in the “Amps” position, an “A” annunciator
will show in the display.
Note: When the VA-1A(-XX) is mounted in the alternator lead and the engine is off, the VA-1A(-XX) may
display up to +/- .3 amps. This is due to any leakage current in the alternator and any offset in the VA-1A(-
XX).
5. Mode Switch: 5. Mode Switch: 5. Mode Switch: 5. Mode Switch: 5. Mode Switch:
The Mode Switch sets the display between “Volts” and “Amps.” The setting of this switch will not affect the
operation of the “High Volts” or “Discharge” warning lights.
V VV VVA-1A Installed in the Battery Lead A-1A Installed in the Battery Lead A-1A Installed in the Battery Lead A-1A Installed in the Battery Lead A-1A Installed in the Battery Lead
The two common methods of installing the VA-1A or VA-1A-XX in the electrical system of your aircraft are in
the battery lead and in the alternator lead. Following are the operating characteristics of the VA-1A installed in
the battery lead.
1. Master On, Engine Off: 1. Master On, Engine Off: 1. Master On, Engine Off: 1. Master On, Engine Off: 1. Master On, Engine Off:
The following describes the operating characteristics of the VA-1A installed in the battery lead with the
master switch on and the engine off.
With the Mode Switch in the “Amps” position, the VA-1A will display the electrical system load on the
aircraft. Since the engine is off, all of the current is being supplied by the battery. The VA-1A will show a
discharging condition (the “Discharge” light will be on) and display an accurate reading of the total current
drain from the battery. With all your electrical equipment off, this will be around 2 to 6 amps. In this mode
of operation any piece of electrical equipment can be checked for proper operation by performing the follow-
ing steps:
A. Note the amps reading on the VA unit.