-
a discrete interface that converts AC
voltages from field devices into DC signals that the processor can use.
AC/DC I/O interface –
-
a device that allows a process to
be switch to either PLC or manual control.
Bypass/control station –
-
a discrete interface, which does
not require an external power source, that is triggered by the change in state
of a normally open or a normally closed contact.
Contact output interface –
-
a discrete module that links a processor
with direct current field devices.
DC I/O interface –
-
a non-continuous signal that has a finite
number of values.
Digital signal –
-
an input circuit that allows a
PLC to receive data from digital field devices.
Discrete input interface –
-
an output circuit that allows a
PLC to send data to digital field equipment.
Discrete output interface –
-
a unique number, assigned to each I/O device,
that corresponds to the device’s location in the rack enclosure.
I/O address –
-
a plug-in assembly, containing two or more
identical input or output circuits, that provides the connection between a
processor and connected devices.
I/O module –
-
and input module in which each
output has a separate return line; can connect field devices powered from
different sources to one module.
Isolated I/O interface –
-
an enclosure, placed in the same area as the
master rack, that contains a local I/O processor, which sends data to and from
the central processing unit.
Local rack –
-
the enclosure containing the CPU or processor
module.
Master rack –
-
the act of channeling two or more signals to
one source using the same channel.
Multiplexing –
-
the location in a PLC that physically
houses plug-in devices, such as I/O modules and supplementary power supplies.
Rack enclosure –
-
a multibit module that uses
thumbwheel stitches to interface between discrete devices and a programmable
controller.
Register/BCD I/O interface –
-
a system where some or all of the I/O
racks are mounted away from the PLC.
Remote I/O subsystem –
-
an enclosure, containing I/O modules and a
remote I/O processor, located away from the CPU.
Remote rack
-
an electrical configuration that
causes a device to receive current when the device is ON.
Sinking configuration –
-
an electrical configuration that
causes a device to provide current when the device is ON.
Sourcing configuration –
-
a discrete interface that allows a controller
to accept signals from TTL field devices, which are 5 V DC-level semiconductor
devices.
TTL I/O interface –
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