Omron H8GN Manual page 23

H8GN
Precautions
!
Caution
Do not use the product in locations subject to flammable or ex-
plosive gases. Doing so may result in explosion.
! Caution
The service life of the output relays depends on the switching
capacity and switching conditions. Consider the actual ap-
plication conditions and use the product within the rated load
and electrical service life. Using the product beyond its service
life may result in contact deposition or burning.
! Caution
Do not disassemble, repair, or modify the product. Doing so
may result in electric shock, fire, or malfunction.
!
Caution
Do not allow metal objects or conductive wires to enter the
product. Doing so may result in electric shock, fire, or malfunc-
tion.
Other Precautions
Store at the specified temperature. If the H8GN has been stored
at a temperature of less than –10 C, allow the H8GN to stand at
room temperature for at least 3 hours before use.
Use the product within the ratings specified for vibration, shock,
submerging in water, and exposure to oil.
Do not use the product in locations subject to dust, corrosive
gases, or direct sunlight.
Use the product within the ratings specified for temperature and
humidity.
The product is designed for 24 VDC. Applying voltages other
than the rated one such as 100 to 240 VAC may damage the
internal elements.
Separate the input signal devices, input signal cables, and the
product from the source of noise or high-tension cables
producing noise.
Separate the product from the source of static electricity when
using the product in an environment where a large amount of
static electricity is produced (e.g., forming compounds, powders,
or fluid materials being transported by pipe).
Do not expose the product to organic solvent such as thinner or
benzine, strong alkali materials, or strong acid materials. Doing
so may damage the product surface.
Application Precautions
1. Do not use the product in locations where condensation may
occur due to high humidity or where temperature changes are
severe.
2. Be sure to wire terminals correctly, with the correct polarity.
3. Maintain the power supply voltage within the allowable
ranges.
4. Connect the power supply through a relay or switch so that
the voltage reaches a fixed value immediately. If the voltage
increases gradually the power supply may be reset or outputs
may turn ON.
5. When the power is turned ON, an inrush current (approx.
15 A) will flow momentarily. Depending on power supply
capacities, the product may not start due to this leakage
current. The power supply must be of a sufficiently large
capacity.
6. For the main power supply or the power supply for input
devices, use a power supply transformer whose primary side
is insulated from the secondary side and whose secondary
side is not grounded.
7. Leaving the H8GN with outputs ON at a high temperature for
a long time may hasten the degradation of internal parts (such
as electrolytic capacitors). Therefore, use the product in
combination with relays and avoid leaving the product as long
as more than 1 month with the output turned ON.
Power Supplies
When turning the power ON and OFF, input signal reception is pos-
sible, unstable, or impossible as shown in the diagram below.
Power
ON
supply
OFF
210 ms 0 to 50 ms
Input Impossible
Unstable
Turn the power ON and OFF using a relay with a rated capacity of 15
A minimum to prevent contact deterioration due to inrush current
caused by turning the power ON and OFF.
When power is turned ON, a starting current flows momentarily.
Therefore, pay attention to the overcurrent detection level of the
power supply used.
Timer Control with Power Start
To allow for the startup time of peripheral devices (sensors, etc.), the
H8GN starts timing operation between 210 to 260 ms after power is
turned ON (see diagram above). For this reason, in operations
where timing starts from power ON, the time display will actually
start from 258 ms. If the set value is 258 ms or less, the time until
output turns ON will be a fixed value between 210 and 260. (Normal
operation is possible for set value of 259 ms or more.) In applica-
tions where a set value of 258 ms or less is required, use start timing
with signal input.
When the H8GN is used with power start in F mode (i.e., accumula-
tive operation with output on hold), there will be a timer error
(approximately 100 ms each time the H8GN is turned ON) due to the
characteristics of the internal circuitry. Use the H8GN with signal
start if timer accuracy is required.
Changing the Set Value
In Counter Operation
When changing the set value during operation, the output will turn
ON if the set value equals the present value.
In Timer Operation
When changing the set value during operation, if the set value is
changed in so that the conditions below are satisfied, the Timer op-
erates in the same way as when the present value reaches the set
value because a constant read-in system is in use. Depending on
the output mode, this may result in output turning ON.
Timer mode UP: Present value
Timer mode DOWN: Elapsed time
(Present value = 0)
Note: When in DOWN mode, the amount set value is changed is
added to or subtracted from the present value.
H8GN
0 to 500 ms
5 ms
Possible Unstable Impossible
set value
set value
25