7
Ⅳ . SETTING OF PRESSURE
1. Switch contact confi guration
・ Composition of contact of this instrument is as shown on
the right.
・ If the instrument is not applied by differential pressure we
call such “
normal condition
” .
・ At normal condition, the contact between COM. and N.C.
is closed, and between COM. and N.O. is open.
・ With increase of differential pressure and reaching the actuation pressure, the contact will be changed
over ; between COM. and N.C. is opened and between COM. and N.O. is closed.
2. Setting of upper limit/ lower limit
・ When differential pressure applied to the instrument is
increased starting from zero and changes over the electric
contact from N.C. (normal close) to N.O. (normal open), the
pressure at this moment is called “
actuation pressure
” .
・ When this differential pressure decreases from the pressure
higher than this actuation pressure activating electrical
contact and returning the contact from N.O. (normal open)
to N.C. (normal close), the pressure at this moment is called
“
reset pressure
” .
・ There is certain difference between actuation pressure and reset pressure and this is called “
dead band
” .
・ There are two types of the instrument. One is called “
upper limit setting type
” type (H) whose scale of
setting knob is adjusted on actuation pressure, the other is called “
lower limit setting type
” type (L)
which is adjusted on reset pressure.
・ Be careful about the difference between the upper and lower limit setting switched and also understand
the relation between the pressure increase/ decrease and the contact composition before designing the
operational sequence.
Depending on the purpose of use, choose the instrument
either
“upper limit setting type”
or
“lower limit setting type”
Difference of contact movement between
“upper limit setting type” and “lower limit
setting type”
In case of 1-6 kPa range with set value 2 kPa.
(dead band is 0.6 kPa)
Adjusting of scale
Name plate
Upper limit
setting type
Adjusted in
activating pressure
In case of “upper limit setting type”
When the differential pressure increases, the
circuit is closed between N.O. and COM. at
2 kPa.
Then as the differential pressure decreases,
the circuit is opened between N.O. and
COM. at 1.4 kPa.
Lower limit
setting type
Adjusted in
reset pressure
In case of “lower limit setting type”
When the differential pressure increases, the
circuit is closed between N.O. and COM. at
2.6 kPa.
Then as the differential pressure decreases,
the circuit is opened between N.O. and
COM. at 2 kPa.
The scale of the setting knob is adjusted for both upper and lower limit setting type at our factory before
shipping. It is not allowed for customers to convert from the upper limit setting to the lower limit setting or
vice versa.
ᵢᶇᶄᶄᶃᶐᶃᶌᶒᶇᵿᶊᴾᶎᶐᶃᶑᶑᶓᶐᶃ
ᵟᶁᶒᶓᵿᶒᶇᶍᶌᴾᶎᶐᶃᶑᶑᶓᶐᶃ
ᵰᶃᶑᶃᶒᴾᶎᶐᶃᶑᶑᶓᶐᶃ
ᵱᶕᶇᶒᶁᶆᶇᶌᶅᴾᶂᶇᶄᶄᶃᶐᶃᶌᶁᶃ
ᵆᶂᶃᵿᶂᴾᶀᵿᶌᶂᵇ
ᵲᶇᶋᶃ
㻱㼤㼜㼘㼍㼚㼍㼠㼕㼛㼚㻌㼐㼕㼍㼓㼞㼍㼙㻌㼛㼒
㼟㼣㼕㼠㼏㼔㼕㼚㼓㻌㼐㼕㼒㼒㼑㼞㼑㼚㼏㼑㻌㼜㼞㼑㼟㼟㼡㼞㼑
ᾝᵌᾒᵌ
ᾒᾞᾜᵌ
ᾝᵌᾞᵌ
ᵧᶌᶁᶐᶃᵿᶑᶃᴾᶍᶄ
ᶂᶇᶄᶄᶃᶐᶃᶌᶒᶇᵿᶊ
ᶎᶐᶃᶑᶑᶓᶐᶃ
