-
Term that refers to the CPU's act of processing the application program
program scan
-
A CPU feature allowing portions of program code to be executed precisely at regular intervals
times interrupt processing
-
These are errr or fault conditions that are detected while the CPU is processing the control program
run-time faults
-
a measure of how long it takes t react to an external input signal and then control an output signal
response time
-
CPU state that, when selected, causes program execution and I/O update on a cyclical basis
RUN mode
-
a special area of memory written to by the control program to control the on/off state of discrete outputs
output image table
-
an important calculation that determines the current consumption of a selected group of I/O modules
power supply loading
-
a CPU feature allowing an external input signal, when generated, to cause the CPU to stop its normal processing to process a special subroutine or portion of code
hardware interrupt processing
-
this nominal value expresses, in ms, the typical time required to process (1024) wrds of programmed instruction
scan rate
-
CPU state, when selected, causes cyclic program execution and I/O image update as in the normal RUN mode, however the real world outputs are not activated
TEST mode
-
a CPU feature allowing inputs to be read or outputs to be controlled whenever the appropriate instruction is encountered, instead of waiting to the normal update at the end of the program scan
immediate I/O update
-
CPU state that, allows the user to selectively override or alter the real world status f inputs and outputs
I/O FORCE mode
-
name given to the duration for which it takes the processor to perform one complete execution of the program and I/O update
cycle time
-
a CPU diagnostic test that monitors program scan to ensure that the normal scan time is not exceeced and is within specified limits
watch dog timer
-
name given to the housing that contains the central processing unit
CPU rack
-
solution intended for applications where downtime or process interruption must be avoided at all costs
fault-tolerant PLC
-
PLC design solution that allows all controlled elements to be brought to a predictable and predetermined safe-state in the case of failures internal or external to the PLC
fail-safe PLC
-
a special memory area reserved for storing the status of the connected discrete inputs
input image table
-
the process of reading the connected inputs and controlling the connected outputs
I/O scan
-
CPU state that, when selectred, causes program execution to be halted and outputs to e disabled
STOP mode
-
permanently stored program, considered part of the PLC-it determines the unique capabilities of the PLC as well as how and when certain system operations are performed
operating system
|
|
