60
APPENDIX H. LITHIUM COIN CELL
H.1 Description
Under normal operating conditions, the 1.5V D cells provide all the power required to operate
the LC-2 datalogger. In order to maintain the correct date and time settings for those periods
when the D cells are removed, the LC-2 datalogger incorporates a 3V lithium coin cell
(Panasonic CR2032) to supply operating current to the internal Real Time Clock.
Since the power requirements of the Real Time Clock circuit are minimal (3µA max.), the clock
will continue to operate for up to 10 years under these conditions.
However, if the lithium cell voltage falls to 2.5V or less, it should be replaced using the
following replacement procedure.
H.2 Replacement Procedure
Materials Required:
•
1/4” Slotted Screwdriver
•
1/4” Nut Driver
•
CR2032 Lithium Coin Cell (Geokon P/N BAT-115)
•
Disposable Grounding Wrist Strap (3M P/N 2209 or equivalent)
Procedure:
1)
Put on the disposable grounding wrist strap and connect to a good earth ground.
2)
Using the 1/4” slotted screwdriver, loosen the four captive screws and remove the datalogger
cover.
3)
Remove the two D cells.
4)
For Models 8002-1-1, 8002-2-1, 8002-3-1: Disconnect the transducer wires at the terminal
block mounted on the battery board by pressing down on the orange tab at the back of the
block and then removing the conductor.
5)
Disconnect the 10-pin DIP connector (ribbon cable) from position J1 on the battery board.
6)
Using the 1/4” slotted screwdriver, remove the four 3/8” 6x32 battery board mounting
screws.
7)
Lift up the battery board and disconnect the two-wire Molex connector (red and black wires)
from the main PCB, which is located below the battery board. Set the battery board aside.
