Refer to document 12P3292, DeltaV Type KJ7000 Series Zone 1 I/O System Installation Instructions for the Discrete Output channels' entity parameters. This document can be found on the DeltaV Documentation Library DVD. This document is in Portable Document Format (.PDF). A letter (A-Z) is appended to the filename and is incremented for each release of the document.
Line fault detection
The I.S. discrete output high-side channels have line fault detection that can be enabled on a channel-by-channel basis as a configuration item. When line fault detection is enabled, the card detects open and short line fault conditions by performing an internal readback of the output to verify its value in both on and off states. The card tests the opposite state of its current value by temporarily changing the output to that value, performing the internal readback, then returning the output to its configured output value. The pulses to the opposite state are never greater than 400 microsecond. High speed inputs that connect to a discrete output channel with line fault enabled must consider these pulses in the input software scheme.
Total cable capacitance of less than 30nF is acceptable. Line fault detection does not work with large inductive or capacitive loads and must be disabled under these conditions.
