Daikin MicroTech II Installation And Maintenance

58 Daikin IM 696-4
Test Procedures
Test Procedures
CAUTION
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. Before
doing this, pump down the compressors. To do this, open
pumpdown switches PS1 and PS2.
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, which
maintains the MCB Static Random Access Memory (SRAM)
and the Real Time Clock (RTC) while power is removed from
the MCB.
The battery degrades with time depending on load,
temperature, and the percentage of time the MCB does not
have po
wer. With an operating temperature under 25ºC,
battery life expectancy is as follows:
Battery usage Typical life Minimum life
1% 10 years 5 years
10% 10 years 5 years
100% 1 year 0.3 years
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,
which 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, replace the battery within 14 days to
avoid complete battery failure and memory loss. Regardless of
the battery status, the MCB board continues execution of the
on-board program.
Note – After battery replacement, the Error LED does not revert
to the normal off condition until one of the following
occurs:
• Power is cycled
to MCB
• The
battery is tested at two minutes after midnight each
day. If battery is normal then, the Error LED reverts to
normal
MCB Data Archiving
All the MCB control parameters and the real time clock
settings are backed up by the MCB using the SRAM. The
SRAM is maintained by the MCB battery when power is
removed from the MCB. To avoid losing the information
stored on the board if battery failure occurs, the MCB
performs a data archiving function once a day, just after
midnight. At this 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 startup and initialization period
by approximately 75 seconds.
MCB “Cold” Reboot
Whenever troubleshooting of the MCB leads to the conclusion
that the MCB is defective, perform a cold reboot before
replacing it. A cold reboot consists of removing the MCB
battery and cycling power to the controller.
MCB LED Power-Up Sequence
The various LEDs on the MCB are shown in Figure 28. When
power is applied to the MCB, the LEDs execute a specific
startup sequen
ce, consisting of the following three main
components:
• The LED Operational Check period
• The MCB Error Code Display period
• The MCB Initialization period
LED Operational Check Period. When power is applied to
the MCB or when the MCB is reset, an operational test of the
16 Binary Input LEDs in the upper left corner and the four
miscellaneous status LEDs at the bottom of the MCB is
performed. This provides a visual check of the operational
status of the LEDs. The following LED sequence should
occur:
1 All 16 of the Binary Input LEDs and all the miscellaneous
LEDs (3 green and 1 red) across the bottom of the MCB,
turn ON for approximately 1–3 seconds and then turn OFF.
2 The miscellaneous LEDs across the bottom of the MCB
sequence ON for one half second and then OFF from left to
right (RS-485 Bus Port Activity, RS-232 Port Activity, IP
Port Activity, and MCB Error).
3 Binary Input LEDs BI-1 through BI-8 are turned ON for
one half second and then turned OFF.
4 Binary Input LEDs BI-9 through BI-16 are turned ON for
one half second and then turned OFF.
If any of these LEDs fail to light as described, replace the
MCB to correct the problem.
Note – Binary Outputs are not tested and remain off during the
LED Operational Check period.
Compressor pumpdown is required before removing power
to the controller or unit damage could occur.
Table 23: Battery life expectancy

Daikin MicroTech II Specifications

General

Brand	Daikin
Model	MicroTech II
Category	Controller
Language	English