9-8
Limits and Digital I/O
Model 2701 User’s Manual
Sink mode — controlling external devices
Each output can be operated from an external supply (voltage range from +5V to +33V
applied through the external device being driven). The high current sink capacity of the
output driver allows direct control of relays, solenoids, and lamps (no additional circuitry
needed).
As shown in Figure 9-3, each of the digital, open-collector outputs includes a built-in pull
up resistor connected to +5V. The output transistor is capable of sinking 250mA from
voltages up to +33V. Each output channel contains a fly-back diode for protection when
switching inductive loads (such as a low power solenoid or relay coils). To use these fly-
back diodes, connect the external supply voltage to pin 7 of the digital I/O port. Make sure
the external supply voltage is b5V and +33V and the current required by the
device does not exceed 250mA.
CAUTION
On pin 7, do not 33V. For the output lines, do not exceed the
maximum sink current. The maximum sink current for an output line
is 250mA. 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 pulled low (0V), the output transistor sinks current
through the external device. In the high state, the output transistor is off (transistor switch
open). This interrupts current flow through the external device.
2701-900-01.book Page 8 Wednesday, August 3, 2011 9:43 AM
Summary of Contents for 2701
Page 344: ...12 CommonCommands 2701 900 01 book Page 1 Wednesday August 3 2011 9 43 AM...
Page 366: ...15 SCPIReferenceTables 2701 900 01 book Page 1 Wednesday August 3 2011 9 43 AM...
Page 393: ...A Specifications 2701 900 01 book Page 1 Wednesday August 3 2011 9 43 AM...
Page 399: ...B Model7700ConnectionGuide 2701 900 01 book Page 1 Wednesday August 3 2011 9 43 AM...
Page 410: ...C StatusandErrorMessages 2701 900 01 book Page 1 Wednesday August 3 2011 9 43 AM...
Page 417: ...D SignalProcessing SequenceandDataFlow 2701 900 01 book Page 1 Wednesday August 3 2011 9 43 AM...
Page 430: ...E MeasurementConsiderations 2701 900 01 book Page 1 Wednesday August 3 2011 9 43 AM...
Page 450: ...G KE2700InstrumentDriver Examples 2701 900 01 book Page 1 Wednesday August 3 2011 9 43 AM...