Tait TB8100 Installation And Operation Manual

Contents

Tait TB8100 Installation And Operation Manual Manual pdf 26 page image

26 Description T801-4 Installation and Operation Manual© Tait Electronics Limited September 20071.4 Back-up BatteryA 3V lithium battery (type CR2032) provides back-up power for theoptional internal GPS receiver. The battery provides back-up power to keepthe module’s RAM alive and to power the real-time clock when thereceiver’s prime power is turned off. RAM is used to store the GPS almanac,ephemeris and last position.Note Configuration data programmed at the factory is stored in non-volatile flash memory which does not require back-up power.Although battery back-up power is not essential, using it can reduce thetime to acquire the first GPS fix:■ hot start less than 20 seconds (typical)■ warm start less than 45 seconds (typical).Without battery back-up power, the GPS receiver, upon power-up, has nomemory of previous navigation data and must perform a cold start. In thiscase the typical time to acquire a fix is less than two minutes. For moreinformation refer to “GPS Fix Acquisition Times” on page 31.Battery Life The lithium battery may last for up to two years, depending on how oftenthe GPS receiver loses prime power. However, we recommend that youcheck the voltage output of the battery every year. The voltage must behigher than 2.5V.Replacing theBattery Follow ESD precautions during this procedure. Refer to “ESDPrecautions” on page 75.1. Disconnect the power supply from the T801-4.2. Remove the top cover.3. Lift the edge of the battery with a thumb or finger.4. Grip the raised edge of the battery with long-nosed pliers and slide itout of the holder.5. Slide the new battery into the holder with the positive pole (+) facingup.6. Refit the top cover and reconnect the power.