beautypg.com

Rockwell Automation 1747-L5xx SLC 500 Modular Hardware Style User Manual User Manual

Page 280

background image

Publication 1747-UM011G-EN-P - June 2008

280

Glossary

offline

When a device is not scanning/controlling or when a programming
device is not communicating with the controller.

offset

A continuous deviation of a controlled variable from a fixed point.

off-state current

For input circuits, the maximum amount of leakage current allowed
from an input device in its off-state.

off-state leakage current

When a mechanical switch is opened (off-state), no current flows
through the switch. Semiconductor switches and transient suppression
components which are sometimes used to protect switches, have a
small current flow when they are 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 must be less than the
minimum operating current rating of the device that is connected.

off-state voltage (max)

The maximum input voltage level detected as an off condition by the
input module.

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 ON or OFF for one program
scan.

online

When a device is scanning/controlling or when a programming device
is communicating with the controller.

on-state voltage drop

The voltage developed across the output driver circuit during the
on-state at maximum load current.