LG Industrial Systems G3F-DA4I, Руководство пользователя

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Chapter 1. INTRODUCION
1 - 2
1.2 Glossary
1.2.1 A - Analog Value
Analog value is a sequentially changing value such as voltage, current, temperature, speed, pressure,
flux, etc.
Temperature, for example, is sequentially changing according to the time. Because this temperature is
not input on the PLC directly, the same analog value of DC voltage (0 to
±
10V) or current (4 to 20mA)
in accordance with the temperature should be input on the PLC through transducer.
1.2.2 D - Digital Value
Digital value is non-sequentially changing value written
as the number like 0, 1, 2, 3. The
signal of on or off is
written as digital value of 0 or 1. There are BCD value
and binary value in the range of digital value.
Analog value isn't written directly on the CPU. For
analog input to the CPU operation, analog converted
to digital value has to be input on the CPU. and for
analog output, the digital of CPU should be
converted to analog.
Number of man
time
[Fig. 1.3] Digital quality
A/D
Conversion
CPU
(Digital
processing
)
D/A
Conversion
Analog
0~ ± 10V or
4~20mA
Analog
0~ ± 10V or
4~20mA
[Fig. 1.4] conversion processing
in the PLC
0
Temperature
time
[Fig 1.1] Analog Value
[Fig 1.2] Example of Transducer
Temperature
0 ~ 1000 ° C
Transducer
-10 ~ 10V
voltage input to
A/D conversion
module
⇒
⇒