Interlock - Keithley 2601B Reference Manual

Series 2600B System SourceMeter® Instrument Reference Manual Section 3: Functions and features

Interlock

The interlock is available on the Models 2611B/2612B/2614B/2634B/2635B/2636B only.
The interlock circuit must be positively activated in order for the high voltage output to be
enabled. The interlock helps facilitate safe operation of the equipment in a test system.
Bypassing the interlock could expose the operator to hazardous voltages that could result in
personal injury or death.
Overview
The Model 2611B/2612B/2614B/2634B/2635B/2636B digital I/O port provides an interlock line for use
with a test fixture switch. When properly used, the output of the SourceMeter instrument will turn off
when the lid of the test fixture is opened. See DUT Test Connections (on page 2-48) for important
safety information when using a test fixture. Follow standard safety and electrical practices by
verifying the correct operation of all components related to system safety, including the interlock.
Operation
When on the 200 V source range, the output of the Model 2611B/2612B/2614B/2634B/2635B/2636B
can only be turned on when the interlock line is driven high through a switch to +5 V (as shown). If the
lid of the test fixture opens, the switch opens, and the interlock line goes low, turning the output of the
®
System SourceMeter instrument off. The output is not automatically turned on when the interlock line
is set high. The output cannot be turned back on until the interlock line is set high.
A signal of > 3.4 V at 24 mA (at an absolute maximum of 6 V) must be externally applied to this pin to
ensure 200 V operation. This signal is pulled down to chassis ground with a 10 kΩ resistor. 200 V
operation will be blocked when the INTERLOCK signal is < 0.4 V (an absolute minimum of −0.4 V).
Figure 90: Using Models 2611B/2612B/2614B/2634B/2635B/2636B interlock
2600BS-901-01 Rev. B / May 2013 3-89