Rockwell Automation 1766-Lxxxx MicroLogix 1400 Programmable Controllers User Manual - Manual (Page 394)

354 Rockwell Automation Publication 1766-UM001H-EN-P - May 2014
Glossary
normally closed
Contacts on a relay or switch that are closed when the relay is de-energized or the
switch is deactivated; they are open when the relay is energized or the switch is
activated. In ladder programming, a symbol that allows logic continuity (flow) if
the referenced input is logic “0” when evaluated.
normally open
Contacts on a relay or switch that are open when the relay is de-energized or the
switch is deactivated. (They are closed when the relay is energized or the switch is
activated.) In ladder programming, a symbol that allows logic continuity (flow) if
the referenced input is logic “1” when evaluated.
off-delay time
The OFF delay time is a measure of the time required for the controller logic to
recognize that a signal has been removed from the input terminal of the
controller. The time is determined by circuit component delays and by any filter
adjustment applied.
offline
Describes devices not under direct communication.
offset
The steady-state deviation of a controlled variable from a fixed point.
off-state leakage current
When an ideal mechanical switch is opened (off-state) no current flows through
the switch. Practical semiconductor switches, and the transient suppression
components which are sometimes used to protect switches, allow a small current
to flow when the switch is in the off state. This current is referred to as the
off-state leakage current. To ensure reliable operation, the off-state leakage
current rating of a switch should be less than the minimum operating current
rating of the load that is connected to the switch.
on-delay time
The ON delay time is a measure of the time required for the controller logic to
recognize that a signal has been presented at the input terminal of the controller.
one-shot
A programming technique that sets a bit for only one program scan.