Omron S8AS User Manual page 39

Internal Configuration
S8AS-48008 (Model with NO Communications and Changeable Parameter Settings)
S8AS-48008N (Model with NO Communications and Unchangeable Parameter Settings)
S8AS-48008R (Model with Communications and Changeable Parameter Settings)
SCREW (M3.5)
AC (L)
Noise
Fuse:
INPUT
filter
12 A
AC (N)
Rectifi-
Inrush
current cation
limit
Harmonic
current
control
Smooth- Rectification
ing
and smoothing
Voltage-ON
detection
Control
circuits
Drive
Process-
circuit
ing
circuit
Rectification and
Auxiliary power
smoothing
supply circuit
• The S8AS compares the measured input voltage, current, and internal
temperature with the preset parameters. These values can be read on the
S8AS's seven-segment display.
• When an error is detected, the branch output will be cut off or an alarm
will be output. The error code and PV will be displayed alternately on the
seven-segment display.
• When an abnormal voltage or current is detected, the semiconductor
relay will cut off the branch output. In the unlikely event that the semicon-
ductor relay cannot cut off an abnormal current or short-circuit current, the
redundant protection circuit, and the short-circuit protection fuse (12.0 A
minimum) will operate to protect the system.
• The S8AS has a built-in temperature sensor, which can detect a tempera-
ture rise inside the S8AS. When the internal temperature exceeds the
detection threshold, the Over-temperature Output (TMP) photoswitch out-
put will turn OFF.
• When an internal circuit has failed, the components can generate exces-
sive heat. As a safety precaution against this kind of failure, the S8AS is
equipped with a function that cuts off operation using a thermal fuse.
Models that support communications have a RS-485 port, and can be con-
nected to a host computer.
Voltage Temperature
detection detection
Processing circuit
(main processing)
Communications between
processing circuits (RS-232C)
Branch output 8
Branch output 7
Branch output 6
Branch output 5
Branch output 4
Branch output 3
Branch output 2
Branch output 1
Current-
Cutoff detection
circuit resistor
Current-
Thermal
detection
fuse
resistor
Voltage
detection
Current
detection
Current-ON
detection
Section 2-2
(S8AS-48008R only)
Communica-
tions
circuit
Display
Switches
circuit
Current-
limiting
Current
circuit
fuse
Cutoff circuit
+V
DC OUTPUT
+V
SCREW (M4)
−V
RS-485
A (−)
B (+)
TRP
LOW
LFE
TMP
COM
TRG+
TRG−
21