H7ET
H7ET
10
JRESET INPUT AND COUNT INPUT
The H7ET operates using a Battery. If the H7ET is connected to
a device that has +V and OUT terminals that are connected with
a diode as shown in the circuit diagram, the circuit indicated by
the arrow 1 or 2 will be formed when the device is turned OFF. As
a result, the H7ET may be reset or count by one. Such devices
should not be connected to the H7ER.
Count input
or reset input
circuit
Internal
If an excessive voltage is applied to the count or reset input
terminals, the internal elements may be damaged.
Ensure that the following voltages are not exceeded:
SPNP/NPN universal voltage input model: 30 VDC
SAC/DC voltage input model:
At count input: 240 VAC (peak voltage: 338V)
240 VDC
At reset input: 3 VDC (no-voltage input)
No-voltage input model: 3 VDC
Do not remove the outer case when voltage is being applied to
the power supply terminals or to the input terminals.
The input for the H7Ej-NFV-jis a high-impedance circuit so
influence from an induced voltage may result in malfunction.
When the input signal wiring is longer than 10 m (stray
capacitance of 120 pF/m, at room temperature), a CR filter or a
bleeder resistor should be connected.
JCOUNT INPUT OR RESET INPUT TO
MORE THAN ONE H7ET COUNTER AT
ATIME
PNP/NPN Universal DC Voltage Input
or
or
Note:H (Reset ON) level must be 4.5 V minimum.
H= 4.7 (kΩ)/N + V
4.7 (kΩ)/N + R
No-voltage Input
or
Note: 1. The leakage current of the transistor used for input
must be less than 1 µA.
2. The forward voltage of the diode must be as low as
possible (i.e., 0.1 V maximum with an IFof 20 µA) so
the voltage between terminals 3 and 4 will be 0.5 V
when the reset input is ON.
JINPUT AND POWER SUPPLY
Do not apply voltage on the Counter if the Counter is a model
that operates with no-voltage input, or the internal circuit of the
Counter may be damaged.
Do not connect any single input signal in parallel to Counter
models operating with no-voltage input and those operating with
voltage input, to avoid malfunction.
When connecting a sensor to the Counter that operates with
no-voltage input, make sure that the sensor has open collector
output.
Sensor
The operation of the Counter may be affected if the line voltage
of the power supply exceeds 500 pF (about 10 m, with parallel
wires of 2 x 2 mm). Keep all wires as short as possible. When
using shielded wire, stray capacitance may occur.
When connecting an open collector input from a transistor to the
Counter that operates with no-voltage input, make sure that the
leakage current of the transistor is 5 µA maximum.
When connecting count input from an SSR to the Counter that
operates with AC/DC voltage input, use OMRON’s G3TA-IA or
G3TA-ID SSR. Otherwise, make sure that the leakage current of
the SSR is 0.1 mA maximum or connect a bleeder resistor in
parallel to the input circuit of the Counter.
Leakage current:
0.1 mA max.
or
or
or
*Bleeder resistor
The voltage between terminals 1 and 2 must be
1.5 V maximum when the SSR is OFF.
JBACKLIGHT POWER SUPPLY
To reduce variation in the brightness of the backlight when using
more than one H7ET with a backlight, use the same power
supply for all the backlights.
When connecting the DC power supply for the backlights, be
sure to connect the polarities correctly.
JINPUT VERIFICATION WITH THE H7ET
TIME COUNTER
The decimal point of the LCD blinks every other second while an
input signal is being applied. If the decimal point is not blinking, the
input signal is not being received correctly. Check the input signal
connections.