Why can't I get the 4200-SCS to output more than 40 volts, even though the program calls for 100 volts?

The most likely cause is that the interlock in your 4200-SCS is not engaged. Interlock is a hardware safety feature, which helps prevent high voltage shock hazard by disabling the 200 V voltage range. To engage the interlock, connect the interlock input on the rear panel of the 4200-SCS to a test fixture, a prober chamber, or other comparable safe enclosure that has a normally-open interlock switch.

The interlock cable is a standard accessory included with every 4200-SCS. For details on interlock wiring and other connections, please refer to Chapter 4 of the 4200-SCS Reference Manual.