YOKOGAWA YewSeries 80 STED Style S, User Manual

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4-2
IM 01B04J01-02E
4.2 Thermocouple Input Type (STED-2 and STED-7
Types)
The Thermocouple input signals are converted into digital data in A/D conversion circuit. The
digital data has signal processing (linearizing computation, RJC computation, and range
conversion) in micro-processor to be Pulse Width Modulation (PWM). The Pulse Width
Modulation (PWM) is converted into 1 to 5 V DC or 4 to 20 mA DC signals in output circuit
after passing through optical insulation circuit.
Handy
Terminal
Output
Circuit
Input
Processing
Circuit
Supply
N–
L+
GND
–
+
–
+
+
–
Output
Circuit
A
B
Power
Supply
Circuit
Insulation Circuit
Micro-
Processor
Insulation Circuit
F
H
C
D
1
2
6
V/I
SPAN
ZERO
Thermocouple Input
Output 1 (1 to 5 V DC)
Output 2 (1 to 5 V DC)
Output 3 (4 to 20 mA DC)
RJC
F0402.ai
Push Switch
for Adjustment
A/D
Conversion
Circuit
No switch for
STED-7 type
Figure 4-2 Functional Block Diagram for Thermocouple Input Type