Omron S8M - 2-4 Basic Function Details

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Basic Function Details Section 2-4
2-4 Basic Function Details
2-4-1 Current Protection Functions
Abnormal Current
Tripping
A different current tripping value can be set for each branch output. Set the
current tripping values between 0.5 and 4.0 A (in 0.1 A units) with the S8M-
CP04 and S8M-CP04-R, or between 0.5 and 3.8 A (in 0.1 A units) with the
S8M-CP04-RS.
The abnormal current tripping type can be set to standard detection (tripping
within 100 ms) or instantaneous detection (tripping within 20 ms).
When the S8M detects an abnormal current, that branch output is cut off by its
semiconductor relay. When the output is cut off, the error code (A11) and
present current are displayed alternately on the seven-segment display and
the Tripping Alarm Output (TRP) is turned OFF.
To reset the alarm, press the Reset Key 15 s after the alarm occurred.
Note After sampling and converting each branch output's current every 1 ms, the
S8M processes the values in the CPU and controls the branch output cutoffs.
This method achieves high-speed, high-accuracy tripping. In addition, to mini-
mize the effects of excessive currents caused by short-circuits, the S8M is
equipped with built-in current-limiting circuits. Consequently, there is a region
in which the current is limited, as shown in the current tripping characteristics
graphs.
Setting
range
Default
value
Tripping
type
Operation Error code and
alarm output
Conditions
required to
reset
0.5 to
4.0 A
(0.5 to
3.8 A in
the
S8M-
CP04-
RS)
4.0 A
(3.8 A
in the
S8M-
CP04-
RS)
Standard When a current
higher than the
set value is
detected, the
branch output is
cut off within
100 ms.
The error code
(A11) and cur-
rent are dis-
played
alternately on
the seven-seg-
ment display
and the Tripping
Alarm Output
(TRP) is turned
OFF.
The Reset Key
can be used to
reset the alarm
once 15 s have
elapsed after
the alarm.
Instanta-
neous
When a current
higher than the
set value is
detected, the
branch output is
cut off within 20
ms.
Abnormal current
value
Current
Standard detection: 100 ms
Instantaneous detection: 20 ms
Tripping Alarm
Output (TRP)
15 s min.
Reset possible