Instruction manual

Unsigned Compares
890USE18300 September 2003 87
Enable Input An outside-the-window unsigned compare block can be enabled either by a Boolean
1 or an always enabled constant. It can be disabled by a Boolean 0 or an always
disabled constant.
If the enable input is a Boolean, it may be produced by:
a digital input from a module on the island
a digital output from the virtual module (See The Virtual Module, p. 28)
an output on the action module (See Using the Action Module as an Input to a
Block, p. 32) written to by the fieldbus master
When the enable input is a Boolean 0 or an always disabled constant, the block is
disabled—the action does not execute and the output is frozen in the state it was in
when the block became disabled. The block continues to process inputs but does
not act on them. If the block becomes enabled, it immediately begins acting on the
latest set of inputs received.
Thresholds Outside-the-window compare blocks require two threshold values, which serve as
the upper and lower bounds of the window. Each TH value needs to be an unsigned
integer in the range 0 to 65 535. TH 1 defines the lower boundary of the window;
TH 2 defines the upper boundary.
Note: The value of TH 2 must be greater than the value of TH 1.