Omron CS1W-SLK11-21 - 06-2004, Manual

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Glossary
GPC An acronym for Graphic Programming Console.
Graphic Programming Console
A programming device with advanced programming and debugging capabili-
ties to facilitate PLC operation. A Graphic Programming Console is provided
with a large display onto which ladder-diagram programs can be written direct-
ly in ladder-diagram symbols for input into the PLC without conversion to mne-
monic form.
handshaking The process whereby two devices exchange basic signals to coordinate com-
munications between them.
header code A code in an instruction that specifies what the instruction is to do.
hexadecimal A number system where all numbers are expressed to the base 16. In a PLC
all data is ultimately stored in binary form. Displays and inputs on Programming
Devices, however, are often expressed in hexadecimal to simplify operation.
Each group of four binary bits is numerically equivalent to one hexadecimal
digit.
host interface An interface that allows communications with a host computer.
Host Link System A system with one or more host computers connected to one or more PLCs via
Host Link Units or host interfaces so that the host computer can be used to
transfer data to and from the PLC(s). Host Link Systems enable centralized
management and control of PLC Systems.
Host Link Unit An interface used to connect a C-series PLC to a host computer in a Host Link
System.
I/O allocation The process by which the PLC assigns certain bits in memory for various func-
tions. This includes pairing I/O bits to I/O points on Units.
I/O Block Either an Input Block or an Output Block. I/O Blocks provide mounting posi-
tions for replaceable relays.
I/O Control Unit A Unit mounted to the CPU Rack to monitor and control I/O points on Expan-
sion CPU Racks or Expansion I/O Racks.
I/O delay The delay in time from when a signal is sent to an output to when the status of
the output is actually in effect or the delay in time from when the status of an
input changes until the signal indicating the change in the status is received.
I/O device A device connected to the I/O terminals on I/O Units, Special I/O Units, etc. I/
O devices may be either part of the Control System, if they function to help con-
trol other devices, or they may be part of the controlled system.
I/O Interface Unit A Unit mounted to an Expansion CPU Rack or Expansion I/O Rack to interface
the Rack to the CPU Rack.
I/O point The place at which an input signal enters the PLC System, or at which an out-
put signal leaves the PLC System. In physical terms, I/O points correspond to
terminals or connector pins on a Unit; in terms of programming, I/O points cor-
respond to I/O bits in the IR area.
I/O refreshing The process of updating output status sent to external devices so that it agrees
with the status of output bits held in memory and of updating input bits in mem-
ory so that they agree with the status of inputs from external devices.