Precautions - Omron H5CX Manual

H5CX

Precautions

!Caution
Do not use the product in locations subject to flammable or ex-
plosive gases. Doing so may result in explosion.
The service life of the output relays depends on the switching
capacity and switching conditions. Consider the actual applica-
tion 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.
Do not disassemble, repair, or modify the product. Doing so may
result in electric shock, fire, or malfunction.
Do not allow metal objects or conductive wires to enter the prod-
uct. Doing so may result in electric shock, fire, or malfunction.
Power Supplies
For the power supply of an input device of the H5CX (except for
H5CX-A11@), use an isolating transformer with the primary and
secondary windings mutually isolated and the secondary winding
not grounded.
H5CX
Input
Input
terminals terminal
Circuit
Isolation transformer is required.
Make sure that the voltage is applied within the specified range,
otherwise the internal elements of the Timer may be damaged.
Do not touch the input terminals while power is supplied. The
H5CX (except for H5CX-A11/-A11S) has a transformerless power
supply and so touching the input terminals with power supplied
may result in electric shock.
When turning the power ON and OFF, input signal reception is
possible, unstable, or impossible as shown in the diagram below.
Power
ON
supply
OFF
200 ms 0 to 50 ms
Input Impossible
Unstable
Turn the power ON and OFF using a relay with a rated capacity of
10 A minimum to prevent contact deterioration due to inrush cur-
rent caused by turning the power ON and OFF.
Apply the power supply voltage through a relay or switch in such a
way that the voltage reaches a fixed value immediately, otherwise
they may not be reset or a timer error may result.
Be sure that the capacity of the power supply is large enough,
otherwise the Timer may not start due to inrush current (approx.
10 A) that may flow for an instant when the Timer is turned on.
Make sure that the fluctuation of the supply voltage is within the
permissible range.
32
Power supply
0 to 500 ms
5 ms
Possible Unstable Impossible
Timer Control with Power Start
To allow for the startup time of peripheral devices (sensors, etc.),
the H5CX starts timing operation between 200 ms to 260 ms after
power is turned ON. For this reason, in operations where timing
starts from power ON, the time display will actually start from 250
ms. If the set value is 249 ms or less, the time until output turns
ON will be a fixed value between 200 and 250. (Normal operation
is possible for set value of 250 ms or more.) In applications where
a set value of 249 ms or less is required, use start timing with sig-
nal input.
When the H5CX is used with power start in F mode (i.e., accumu-
lative operation with output on hold), there will be a timer error
(approximately 100 ms each time the H5CX is turned ON) due to
the characteristics of the internal circuitry. Use the H5CX with sig-
nal start if timer accuracy is required.
Input/Output
The H5CX (except for H5CX-A11/-A11S) uses a transformerless
power supply. When connecting a relay or transistor as an exter-
nal signal input device, pay attention to the following points to pre-
vent short-circuiting due to a sneak current to the transformerless
power supply. If a relay or transistor is connected to two or more
Timers, the input terminals of those Timers must be wired prop-
erly so that they will not differ in phase, otherwise the terminals
will be short-circuited to one another.
Incorrect
H5CX
Contact or transistor for
external input signal
Input
terminal
Input
terminal
Correct
Input
terminal
Input
terminal
H5CX
Short-circuit current
Power supply
Power supply