Rockwell Automation 1747-L5xx SLC 500 Modular Hardware Style User Manual - Manual (Page 281)

Publication 1747-UM011G-EN-P - June 2008
Glossary 281
operating voltage
For inputs, the voltage range needed for the input to be in the
On-state. For outputs, the allowable range of user-supplied voltage.
output device
A device, such as a pilot light or a motor starter coil, that is energized
by the programmable controller.
output scan
The controller turns on, off, or modifies the devices connected to the
output terminals.
PCCC (programmable controller communication commands)
points per common
The number of input or output points connected to a single return
(common) or supply (vcc).
poll message
A poll message is a point-to-point transfer of data sent by the scanner
that solicits a response from a single device. The device responds with
its data bit and status bit.
processor
A Central Processing Unit. (See CPU.)
processor files
The set of program and data files resident in the controller.
program file
Areas within a processor that contain the logic programs. SLC
controllers support multiple program files.
program mode
When the controller is not scanning the control program.
program scan
A part of the controller’s operating cycle. During the program scan,
the logic program is processed and the Output Image is updated.