Datasheet
Contact Protection Box: CD-P11, CD-P12
To connect a switch unit to a contact protection box, connect the lead 
wire from the side of the contact protection box marked SWITCH to 
the lead wire coming out of the switch unit. Keep the switch as close 
as possible to the contact protection box, with a lead wire length of no 
more than 1 meter.
Contact Protection Box Connection
Hysteresis is the distance between the position at which piston 
movement operates an auto switch to the position at which reverse 
movement turns the switch off. This hysteresis is included in part of 
the operating range (one side).
Note) Hysteresis may fluctuate due to the operating environment.
Please contact SMC if hysteresis causes an operational problem.
Auto Switch Hysteresis
Contact Protection Box/Dimensions
Contact Protection Box Internal Circuit
Contact Protection Box Specifications
Part no.
Load voltage
Max. load current
CD-P11 CD-P12
∗ Lead wire length — Auto switch connection side 0.5 m 
Load connection side 0.5 m
100 VAC or less
25 mA
200 VAC
12.5 mA
24 VDC
50 mA
Prior to Use
Auto Switches Common Specifications 2
Specific Product Precautions
Auto switch
Switch 
operating 
position
(ON)
Hysteresis
Reed auto switch: 2 mm or less
Solid state auto switch: 1 mm or less
Note)
Switch 
operating 
position
(OFF)
<Applicable switch models>
D-A9/A9V
The auto switches above do not have a built-in contact protection 
circuit. A contact protection box is not required for solid state auto 
switches due to their construction.
q Where the operation load is an inductive load.
w Where the wiring length to load is greater than 5 m.
e Where the load voltage is 100 VAC.
Therefore, use a contact protection box with the switch for 
any of the above cases:
The contact life may be shortened (due to permanent energizing 
conditions.)
When the load voltage is increased by more than 10% to the rating 
of applicable auto switches above, use a contact protection box 
(CD-P11) to reduce the upper limit of the load current by 10% so 
that it can be set within the range of the load current range, 110 
VAC.
CD-P11
CD-P12
Surge absorber
Zener diode
Choke
coil
OUT Brown
OUT Blue
OUT (+) Brown
OUT (–) Blue
~
Choke
coil
Before handling auto switches, refer to “Handling Precautions for SMC Products” (M-E03-3) for Auto Switches
Precautions.
14










