Omron CS1W-SLK11-21 - 06-2004 Manual page 190

Peripheral Device
peripheral servicing
PID Unit
polling
present value
printed circuit board
Programmable Controller
Programming Console
Programming Device
PROM
PROM Writer
prompt
protocol
PV
Rack
Glossary
Devices connected to a PLC System to aid in system operation. Peripheral de-
vices include printers, programming devices, external storage media, etc.
Processing signals to and from peripheral devices, including refreshing, com-
munications processing, interrupts, etc.
A Unit designed for PID control.
The process whereby a device consecutively sends signals to other devices in
the same network to pass data back and forth, e.g., as in a data link.
The current value registered in a device at any instant during its operation.
Present value is abbreviated as PV. The use of this term is generally restricted
to timers and counters.
A board onto which electrical circuits are printed for mounting into a computer
or electrical device.
A computerized device that can accept inputs from external devices and gen-
erate outputs to external devices according to a program held in memory. Pro-
grammable Controllers are used to automate control of external devices.
Although single-unit Programmable Controllers are available, building-block
Programmable Controllers are constructed from separate components. Such
Programmable Controllers are formed only when enough of these separate
components are assembled to form a functional assembly, i.e., there is no one
individual Unit called a PLC.
The simplest form or programming device available for a PLC. Programming
Consoles are available both as hand-held models and as CPU-mounting mod-
els.
A Peripheral Device used to input a program into a PLC or to alter or monitor
a program already held in the PLC. There are dedicated programming devices,
such as Programming Consoles, and there are non-dedicated devices, such
as a host computer.
Programmable read-only memory; a type of ROM into which the program or
data may be written after manufacture, by a customer, but which is fixed from
that time on.
A peripheral device used to write programs and other data into a ROM for per-
manent storage and application.
A message or symbol that appears on a display to request input from the op-
erator.
The parameters and procedures that are standardized to enable two devices
to communicate or to enable a programmer or operator to communicate with a
device.
See present value.
An assembly that forms a functional unit in a Rack PLC System. A Rack con-
sists of a Backplane and the Units mounted to it. These Units include the Pow-
er Supply, CPU, and I/O Units. Racks include CPU Racks, Expansion I/O
Racks, and I/O Racks. The CPU Rack is the Rack with the CPU mounted to it.
An Expansion I/O Rack is an additional Rack that holds extra I/O Units. An I/O
Rack is used in the C2000H Duplex System, because there is no room for any
I/O Units on the CPU Rack in this System.
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