CKD PPX Series - Usage and Maintenance Precautions; Overcurrent and Surge Protection; Reverse Current Protection and Maintenance

Precautions
PPX
Series
During Use & Maintenance
24
When unit is changed
If the product for domestic market is used with unit change
function, and if unit other than MPa and kPa is used, put
the unit label enclosed with the product on the unit display
section in the control.
PPX bar
Putting
seal label
<Unit seal label>
kPa
MPa
kgf/cm
3
bar
psi
mmHg
inHg
Pressure unit label
WARNING
Do not apply overcurrent.
Due to short-circuit of load, if overcurrent applies to the
pressure switch, the switch could be damaged or ignite.
Install a fuse on output or power line as a overcurrent
protective circuit.
CAUTION
Do not disassemble the product.
Disassembling the product could result in damage or deterioration
of the product. CKD will not guarantee the performance after
disassembling. When replacing or moving the product, remove
the sensor without disassembling pressurized port.
Stop machinery and equipment, then check the
safety before operating the product.
The case is made of resin. Do not use solvent, alcohol or any
other cleaning agent, etc., to remove contamination, etc., or resin
could be corroded or damaged. Wipe contaminations with a well
wrung rag, etc., after soaked in weakened neutral detergent.
Care must be taken for reverse current caused by
disconnection or wiring resistance. When components including
pressure switches are connected to the same power source of
pressure switch, if (-) sides of output and power lines are short-
circuited to check input devices of the control panel, or if (-) side
of power line is disconnected, reverse current may apply to the
output circuit of pressure switch, causing damages.
Take countermeasures as followings to prevent
damages caused by reverse current.
Do not concentrate current to the power line, especially, (-)
side power line, and use wire as thick as possible.
Limit numbers of components connected to the same
power source of pressure switch.
Connect a diode in series to the pressure switch output
line to prevent reverse current.
Connect a diode in series to power line (-) side of the
pressure switch to prevent reverse current.
Other components
Control panel
Main circuit
PLC input
Diode to prevent
reverseow
Pressure switch
Current
from other
components
Disconnection
Test SW or
short-circuit
Care must be taken for surge current leading.
When pressure switch shares the power supply with
inductive loads that create surge current such as,
solenoid valves or relays, if the circuit is closed with
inductive loads activated, surge current could lead
to the output circuit, causing damages.
Take countermeasures as followings to prevent
damage caused by surge current leading.
When components are connected with connectors,
if a connector is dislocated during energizing, the
output circuit could be damaged because of the
reason above. Turn off the power before dislocating
a connector.
Separate the power supply for outputs creating inductive
load such as solenoid valve and relay, etc. and inputs such
as pressure switch, etc.
If the power cannot be separated from the inductive load,
install a surge absorbing element(s) per load. The surge
absorbing element(s) connected to PLC, etc. merely
protects the unit connected.
Connect surge absorbing element(s) to the points as
following to reduce damages when lines are disconnected.
Input components Input components Input components
Pressure switch
Main circuit
Relay
Surge current
Solenoid valve
Surge absorbing element
(later installation)
Disconnection or circuit shutdown
caused by emergency stop
Surge absorbing
element (integrated)
Output of PLC
PC
ON