I/O Wiring

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Input Sink Module The figure on the right depicts an input sink module. Note that one terminal of the module is connected to the DCV common. Now note the input device. One side of the input device is wired to +VDC. According to the definition, this input device is connected type source, (one connection of a souce device or module is connected to +VDC.) These connections define another fact, sink modules are wired with source devices.

A sink module supplies the I/O power supply return path or the path to the DCV common.

The polarity of a module can always be determined by looking at how the field devices are wired to the module. In the figure on the right, since one side of the field device is wired the +VDC, as stated above the device is sourcing. Since the field device is source, then by definition the module must be sink.

Ouptut Sink Module The figure on the right depicts an output sink module. Note that one terminal of the module is connected to the DCV common. Now note the output device. One side of the output device is wired to +VDC. According to the definition, this output device is connected type source, (one connection of a souce device or module is connected to +VDC.) These connections define another fact, sink modules are wired with source devices.

A sink module supplies the I/O power supply return path or the path to the DCV common.

The polarity of a module can always be determined by looking at how the field devices are wired to the module. In the figure on the right, since one side of the field device is wired the +VDC, as stated above the device is sourcing. Since the field device is source, then by definition the module must be sink.

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John G. (Skip) Todora   ⇔   Late updated: November 11, 2009