Chapter 7 Usage of Various Functions
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3) Parameter setting
(1) Scaling function
This function convert automatically range when the inout/output range is not matched.
In case that input/output is current , this function is useful that external equapment’ range is not matched each other.
(MASTER-K120S series converts range automatically as following : 0 ~ 20mA ⇔ 4 ~ 20mA)
Conversion method is as below
• scaling conversion value (A/D conversion) = [(data of 0 ~ 20 ㎃) – 800] x 4000/3200
example) in case of 8㎃input at range 0 ~ 20 ㎃
before the scaling conversion : 8㎃ / 5㎂ = 1600
after the scaling conversion : (1600 –800) x 1.25 = 1000
• scaling conversion value (D/A conversion) = [(data of 4 ~ 20 ㎃) x 3200/4000] + 800
example) in case of ‘1000’ output at range 4 ~ 20㎃
current output value before the scaling conversion : 1000 x 5 ㎂ = 5㎃
current output value after the scaling conversion : (1000 x 0.8) + 800 = 1600
1600 x 5 ㎂ = 8 ㎃
4000
0
0㎃ 20 ㎃
4000
0
4㎃ 20 ㎃
Resolution : 20 ㎃/4000 = 5 ㎂
800
-1000
Resolution : 20 ㎃/3200 = 6.25 ㎂