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3.6 Calibration
Because this product is adjusted beforehand, there is no necessity for calibration.
However, if the operating point of an alarm output shifts, please adjust in the next way.
(1) After turning on the auxiliary power, perform preliminary energization for 15 minutes.
(2) When the input equivalent to the minimum display is applied, in order that it may become the minimum
display, set value CBIAS is set up.
Next, when the input equivalent to the maximum display is applied, in order that it may become the
maximum display, it sets up by set value CSPAN.
Calibration is finishing, if the above is checked again and the display is correct.
In addition, please refer to the 4.5 section "setting mode" about setting of set value CBIAS and CSPAN.
(3) Please perform the check of an operation value, a reset value, and a dead band.
4. Block-diagram and principle of operation
4.1 Block-diagram
(＋)
1
Filter
INPUT
protection
(－)
2
circuit
＋
( )
～
Power supply
AUX.
circuit
SUPPLY
－ ～
( )
From mounting
base
4.2 Principle of operation
(1) The inputted voltage or current passes along a filter protection circuit, and becomes the DC voltage
below constant voltage. This voltage goes into an amplifier.
(2) The input is converted into the suitable voltage range in an amplifier.
This voltage constitutes an input of an A/D converter.
(3) The data converted into digital one by the A/D converter are sent to CPU.
A/D converter has 16-bit resolution and performs operation and conversion with 1MHz clock.
Based on the scaling range that had this data set up, it calculates within CPU.
And the measurement value scaling by the LCD is displayed.
(4) The operation value and measurement value, which was set up beforehand, are compared, and the relay
and LED are operated.
(5) The front key switch makes each setting change.
(6) The value set up by the switch is saved at non-volatile memory (E
ROM has the capacity of 128×16 bits.
A/D
Amplifier
converter
Non-volatile
memory
2
E
PROM
Key switch
LCD
driver
CPU
＊ In case of 4 contact output
MODE
UP
[Normally open contact
ENT
SHIFT
RY
RY
RY
RY
Relay output circuit
2
PROM).
12
FSDLC-220-047
1 0 0 . 0
%
LCD display
AL1 AL2 AL3 AL4
LED display
6
AL1
7
AL2
5
COM
6
AL3
7
AL4
5
COM
UNIT n
UNIT n+1
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