K6 Configuration
When the K6 configured as an O/P providing GND or OPEN and the K6 bank only needs the referenced ground, is VCC required?
With a low side drive output the VCC would not be required to be connected to the bank.
When the K6 is configured as an INPUT sensing 28 V or OPEN and 28 V reference ground is required, is the VCC also required?
This is a voltage contact sensing in which the reference ground needs to be wired. However, when no current pull-up is required to measure the voltage, the VCC does not need to be supplied to this bank.
In the general cases where the K6 is sensing a voltage level as an input, is only the reference ground required?
Yes, this is correct.
In the general cases where the K6 is providing a voltage level as an output are both VCC and the reference ground are required?
When configured with high and low drive capability (push – pull) both VCC and GND must be connected to the bank. As an output (sinking current) GND must be connected. External VCC is not required.
When the K6 is configured as an OUTPUT providing 28 V or OPEN, and the K6 bank only requires VCC, is the reference ground required?
Normally yes, but please note that Built-in-Test (BIT) requires GND return to function.
When the K6 is configured as an INPUT sensing GND or OPEN and the VCC is required (VCC referenced to the ground it is sensing), does the reference ground also need to be supplied to the K6 bank?
Yes, both VCC and GND are required to be supplied when using a pull-up (also GND is required for BIT).
Note: This also applies to the latest discrete I/O modules, DT1/DT4.