ACR Electronics SmartReader Plus Bedienungsanleitung PDF herunterladen (Seite 56)

SmartReader Data Loggers

then be wired to either of the "- Common" terminals.

Figure 7-9: Using the Battery Switch

The maximum current that the battery switch can source is 100mA. Battery supply voltage

can be from 9 to 25 volts. Short circuit protection is continuous at 9 volts, but only one second

at higher voltages.

Things you should know about batteries

When using batteries for powering your external sensors and transducers, you should keep in

mind these key points:

1. The rated voltage of a battery only applies to initial use. Once under load, the voltage will

decrease gradually until completely drained (refer to Figure 7-8). By knowing how the

battery voltage is affected through use you can make sure that the voltage requirements

of your external transducers will be met. A good rule of thumb to follow is to exceed the

minimum required input voltage for your transducers by at least two times (where

acceptable).

2. Nickel-Cadmium (rechargeable) batteries self-discharge at a rate approximating 1% of

their remaining capacity per day. This should be taken into account for extended logging

sessions.

Determining how long your batteries will last

To estimate how long your batteries will successfully power your external sensors and

transducers, you will need to know both the capacity of the batteries as well as the proposed

resistance presented to them by the load (your own transducers).

Battery capacity, usually expressed in milliampere-hours (mAh), is the total amount of

electrical charge a cell can store or deliver. Unfortunately, most commercially-available

batteries are sold without any of this capacity information listed. To get this information you

can usually call one of their local representatives.

As a general guide, most good quality nine volt batteries have a capacity of approximately 500

mAh. This means, at an average continuous current draw of 50mA, it will deliver

approximately ten hours of service.

1 2 ... 51 52 53 54 55 56 57 58 59 60 61 ... 102 103

Keine Kommentare

ACR Electronics SmartReader Plus Bedienungsanleitung Seite 56