IM710 41
Test Procedures
When troubleshooting the various MicroTech II components,
it may be necessary to remove power to the controller by
opening system switch S1 in the main control panel.
Table 27 on page 50 in the “Parts List” section at the end of
this manual includes a listing of MicroTech II related part
numbers.
Troubleshooting Main Control Board
(MCB)
MCB Battery
Standby power is provided by a 3 VDC lithium battery and
will maintain the MCB Static Random Access Memory
(SRAM) and the Real Time Clock (RTC) while power is
removed from the MCB.
The battery will degrade with time depending on load, tem-
perature, and the percentage of time the MCB does not have
power. With an operating temperature under 25 ºC, battery
life expectancy will be as follows:
A battery test is performed each time the MCB power-up
diagnostics are executed. The minimum voltage needed to
sustain the SRAM and RTC is 2.0 VDC. A warning occurs
when the battery voltage drops below approximately 2.5
VDC and is indicated by the red MCB Error LED blinking
after the Main Control Board Power-Up Sequence described
below is completed. This warning signals that the battery is
reaching the end of its useful life and should be replaced.
Once a battery warning alarm occurs, the battery should be
replaced within 14 days to avoid complete battery failure and
memory loss. Regardless of the battery status, the MCB
board will continue execution of the on-board program.
Note: After battery replacement, the Error LED will not
revert to the normal off condition until one of the following
occurs:
1. Power is cycled to MCB
2. The battery is tested at two minutes after midnight each
day. If battery is normal then, the Error LED reverts to
normal.
3. A battery test command is issue with a PC using the
MicroTech II Service Tool.
MCB Data Archiving
All the MCB control parameters and the real time clock set-
tings are backed up by the MCB using the SRAM. The
SRAM is maintained by the MCB battery when power is
removed from the MCB. Because battery failure may occur
and to avoid losing the information stored on the board, the
MCB performs a data archiving function once a day, just
after midnight. At the same time, all the MCB control
parameter settings are archived to a file stored in the MCB
FLASH memory.
If the MCB is Powered up with a low or defective battery (or
no battery), the most recently archived data is restored to the
controller. Note: When this archived data restoration process
occurs, it increases the controller start up and initialization
period by approximately 75 seconds.
MCB “Cold” Reboot
Whenever troubleshooting of the MCB leads to the conclu-
sion that MCB is defective, a “cold” reboot should be per-
formed before the MCB is condemned and replaced. A
“cold” reboot consists of removing the MCB battery and
cycling power to the controller.
Table 24: Battery Life Expectancy
Battery Usage Typical Life Minimum Life
1% 10 years 5 years
10% 10 years 5 years
100% 1 year 0.3 years
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