Overview - Keithley 2302 Instruction Manual

5-2 Relay Control

Overview

The power supply can be used to control up to four external relays. The control circuit is made
up of four peripheral drivers, a +5VDC source (250mADC maximum), a coil diode suppression
connection, and a chassis ground return. The drive for the relay may be provided by the supplied
+5VDC source or an external DC voltage source.
NOTE
Figure 5-1
control an external relay driven by an external power source. As shown in the illustration, volt-
age applied to the power supply must not exceed 24VDC and current for the relay circuit must
not exceed 100mADC per channel.
Figure 5-2
control an external relay driven by the internal power source. If the supplied +5VDC source is
used to drive the external relay, the relay circuit must not exceed 250mADC total (100mADC
per channel).
Note that the coil protection diodes are built in to the power supply driver (the user is not
required to add external protection diodes to protect the relay coils).
CAUTION
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The Model 2306-VS cannot be used for relay control.
shows the simplified power supply control circuit and a typical configuration to
shows the simplified power supply control circuit and a typical configuration to
To prevent damage to the power supply that is not covered by the warranty, al-
ways make sure to:
• Connect suppression diodes (pin 7) to the appropriate voltage source (the
appropriate voltage source will either be an external power source or pin 8
if using the internal source).
• Never exceed the voltage and current limits of the power supply's relay con-
trol port:
External Source: 24VDC, 100mA per channel
Internal source:
1) 5VDC, 250mA maximum total current from all channels combined.
2) 100mA per channel maximum (not to exceed the 250mA maximum
total current).
• Connect and disconnect relay drive circuits with the power supply power
OFF.