Keithley 6221 User Manual

Model 6220/6221 Reference Manual Limit Test and Digital I/O 9-7
Return to Section 9 topics
CAUTION Do not exceed +33V maximum voltage on pin 5 of the digital I/O
port and do not use any output line to sink >500mA. Exceeding
these limits may cause damage to the instrument that is not
covered by the warranty.
An externally powered relay connected to the digital output port is shown in
Figure 9-4. Other externally powered devices can be similarly connected by
replacing the relay with the device. When the output line is set LO (0V), the output
transistor sinks current through the external device. In the HI state, the output
transistor is off (transistor switch open). This interrupts current flow through the
external device.
Figure 9-4
Controlling externally powered relays
+5V
1kW
Pull Up
Resistor
Pin 9 - Digital Ground
Pin 1 - Digital Output #1
Pin 5 - External Voltage Flyback Connection
Digital Output #1
Flyback Diode
To three other
digital outputs
Relay
Coil
+
(+
-
(-
External Power
(+5V to +33V)
Transistor
Switch
Flyback
Diode
Equivalent Circuit
Relay
Coil
External Power
(+5V to +33V)
Model 622x
33V
Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176 - TestEquipmentDepot.com

Keithley 6221 Specifications

General

Interface	GPIB, RS-232
Communication Interface	GPIB, RS-232
Current Sourcing Accuracy	±(0.03% of output + 20 pA)
Current Sinking Accuracy	±(0.03% of output + 20 pA)
Output Resolution	100 fA
Output Accuracy	±(0.03% of output + 20 pA)
Power Requirements	100 V to 240 V AC, 50/60 Hz