h3cr-a Omron Corporation, h3cr-a Datasheet - Page 19

• Manufacturer Part Number: h3cr-a
• Description: Solid-state Multi-functional Timer
• Manufacturer: Omron Corporation

Safety Precautions (H3CR-A)
Refer to Safety Precautions for All Timers.
Note: The following precautions apply to all H3CR-A models.
■ Power Supplies
For the power supply of an input device of the H3CR-A@/-A@S/-AP,
use an isolating transformer with the primary and secondary
windings mutually isolated and the secondary winding not grounded.
The H3CR-A@/-A@S/AP’s power supply terminal 2 is a common ter-
minal for input signals to the Timer. Do not disconnect the wires on
terminal 2, otherwise the internal circuitry of the Timer will be dam-
aged.
Make sure that the voltage is applied within the specified range, oth-
erwise the internal elements of the Timer may be damaged.
Correct
Incorrect
G,
5, 6, 7
S,
G,
Input terminal
Input device
5, 6, 7
R
2
S,
5, 6, 7
G, S, R
Input device
R
2
Input
terminal
H3CR-A
H3CR-A
terminal
Input
transformer
Isolation
10
H3CR-A
2
Isolation transformer is required.
10
2
2
10
Power supply
Power
supply
■ Input/Output
Relationship between Input and Power
Supply Circuits (except for H3CR-A8E)
The H3CR-A (except for H3CR-A8E) uses transformerless power
supply. When connecting a relay or transistor as an external signal
input device, pay attention to the following points to prevent 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 properly so that they will not
differ in phase, otherwise the terminals will be short-circuited to one
another.
It is impossible to provide two independent power switches as shown
below regardless of whether or not the Timers are different in phase.
Incorrect
Correct
Contact or transistor for
external input signal
Input
terminal
Input
terminal
Input
terminal
Input
terminal
Input
terminal
Input
terminal
H3CR-A
Short-circuit current
Power supply
H3CR-A
Power supply
Power supply
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