Hitachi HIDIC MICRO-EH Applications Manual page 308

Chapter 15 Daily and Periodic Inspections
In order to use the functions of the MICRO-EH in the optimal conditions and maintain the system to operate normally, it
is essential to conduct daily and periodic inspections.
(1) Daily inspection
Verify the following items while the system is running.
Item
Unit LED display
*1
*1: The MICRO-EH indicates the error contents using the combination of lit/flashing/not lit status of OK and
RUN lamps. For details, see the error code list in Chapter 12.
*2: If the power supply for the basic unit is left turned off without replacing the battery after the OK lamp was
flashing, the memory contents may be destroyed. Exercise caution when the system power is turned off for a
long period of time, since this error may not have been detected and the memory contents may have already
been destroyed.
(2) Periodic inspection
Turn off the power for the external I/O circuit and check the following items once every six months.
Programming device to
CPU
Power supply
I/O module
Battery
(Lithium battery)
Installation and
connecting areas
Ambient environment
Spare parts
Program
(3) Life of the power module
Numbers of electrolytic condensers are used in the power module. Electrolytic condensers have a lifetime and it is
believed that the life is reduced by half when the ambient temperature rises 10 °C.
When stocking spare parts, the standard for consideration is that the power module has a life of approximately five
years when used at the rated ambient temperature (30 °C). Also, to extend the life of the module, consider the air
circulation around the module and ambient temperature when installing it.
Table 15.1 Items for daily inspection
LED
Normal status
display
POW Lighting
RUN Lighting
(in RUN
OK Lighting
Table 15.2 Items for periodic inspection
Part Item
Check operation of
programming device
Check for voltage fluctuations
Output relay life
LED
External power voltage
Check voltage and life
(1) All modules are securely
fixed
(2) All connectors fit snugly
(3) All screws are tightened
(4) Damage and deterioration
of each cable
(1) Temperature
(2) Humidity
(3) Other
Check number of parts, storage
condition
Check program contents
Chapter 15 Daily and Periodic Inspection
Main cause of error
Power supply error, etc.
When not lit:
Microcomputer malfunction, memory error, etc.
status) When flashing:
Syntax error, congestion error, etc.
When not lit:
Microcomputer malfunction, memory error, etc.
When flashing:
Battery error *2
Check criteria
Must be able to be connected online.
All switches and display lamps work
normally.
85 to 264 V AC
Electrical life
Mechanical life 20 million times
Turns on/off correctly
Within the specification for each I/O See the I/O specifications
Is the OK lamp flashing?
Check to see if it has been less than
2 months since the last exchange.
There should be no problem.
0 to 55 °C
5 to 95 % RH (no condensation)
No dust, foreign matter, vibration
There should be no problem.
Compare the contents of the latest
program saved and CPU contents,
and make sure they match.
15-1
Remarks
Tester
200,000 times See the relay contact life
curve (Chapter 10).
(Chapter 6).
Tighten
Check insertion
Tighten
Visual check
-
-
Check both master and
backup.