Update pinmaps in nidcpower_source_dc_voltage example to have one pin/channel (#224)

* Update pinmaps in nidcpower source voltage examples to have one pin and one channel

* Revert changes in multisite pinmap to have multiple channels/pins

* Add note in Readme.md

Author: samchris007

examples/nidcpower_source_dc_voltage/NIDCPowerSourceDCVoltage.pinmap

@@ -7,14 +7,12 @@
 	</Instruments>
 	<Pins>
 		<DUTPin name="Pin1" />
-		<DUTPin name="Pin2" />
 	</Pins>
 	<PinGroups></PinGroups>
 	<Sites>
 		<Site siteNumber="0" />
 	</Sites>
 	<Connections>
 		<Connection pin="Pin1" siteNumber="0" instrument="DCPower1" channel="0" />
-		<Connection pin="Pin2" siteNumber="0" instrument="DCPower1" channel="1" />
 	</Connections>
 </PinMap>

examples/nidcpower_source_dc_voltage/README.md

@@ -29,4 +29,8 @@ This example requires an NI SMU that is supported by NI-DCPower (e.g. PXIe-4141)
 
 To simulate an NI SMU in software: open `NI MAX`, right-click `Devices and Interfaces`,
 select `Create New...`, and select `Simulated NI-DAQmx Device or Modular Instrument`.
-SMUs are in the `Power Supplies` category.
+SMUs are in the `Power Supplies` category.
+
+### Note
+
+- In order to run the measurement with `NIDCPowerSourceDCVoltageMultiSite.pinmap`, it is required to have an NI SMU with 4 or more channels.