looking at photos of the switches
the KJD17B has the solenoid connectly to the switched output terminals 14 & 24
the CK21 has only one end of the solenoid connected to the switched output 2
the other end of the solenoid goes to a small 5th terminal you have to connect to switched output 1
this enables you to add one or more normally closed remote E-stop switches
use terminals 3 & 4 as the mains input
if you don't need to add any E-stop switches you can use either switch
John
Edited By john swift 1 on 13/04/2019 09:45:52