Table 2-6: Digital I/O terminal functions
U1-U12 C1-C4
General I/O
ü ü
Pulse-Width Modulation Output
ü ü
Timer Input
ü ü
Interrupt
ü ü
Quadrature
ü ü
2.1 Power input
The data logger requires a power supply. It can receive power from a variety of sources, operate
for several months on non-rechargeable batteries, and supply power to many sensors and
devices. The data logger operates with external power connected to the green BAT and/or CHG
terminals on the face of the wiring panel. The positive power wire connects to +. The negative
wire connects to -. The power terminals are internally protected against polarity reversal and high
voltage transients.
In the field, the data logger can be powered in any of the following ways:
l 10 to 18 VDC applied to the BAT + and – terminals
l 16 to 32 VDC applied to the CHG + and – terminals
To establish an uninterruptible power supply (UPS), connect the primary power source (often a
transformer, power converter, or solar panel) to the CHG terminals and connect a nominal 12
VDC sealed rechargeable lead-acid battery to the BAT terminals. See Power budgeting (p. 120)
for more information. The Status Table ChargeState may display any of the following:
l No Charge - The charger input voltage is either less than +9.82V±2% or there is no charger
attached to the terminal block.
l Low Charge Input – The charger input voltage is less than the battery voltage.
l Current Limited – The charger input voltage is greater than the battery voltage AND the
battery voltage is less than the optimal charge voltage. For example, on a cloudy day, a
solar panel may not be providing as much current as the charger would like to use.
l Float Charging – The battery voltage is equal to the optimal charge voltage.
l Regulator Fault - The charging regulator is in a fault condition.
2. Wiring panel and terminal functions 8
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