Rockwell Automation 1747-L40 SLC 500 Fixed Hardware Style - Manual (Page 211)

Glossary
G–2
DTR Dialing (5/03 only) — type of modem that lets you dial a number or
end a call based on the status of the RS–232 DTR (Data Terminal Ready)
signal. To program the modem initialization string and phone number into
the internal memory of the modem, use a dumb terminal (or PC running
terminal emulation software like Procomm, Window’s Terminal, or PBASE).
Once you have programmed the modem, activate the DTR signal to dial the
number, or deactivate the DTR signal to end the call.
EEPROM — Electrically Erasable Programmable Read Only Memory
module used to store, back up, or transfer SLC 500 programs. The SLC 500
can read and write to an EEPROM.
Flash EPROM — Flash Erasable Programmable Read Only Memory
module. It combines the programming versatility of EEPROMs with the
security precautions of UVPROMs. This means that you have the option of
leaving your EPROM programs write protected or unprotected.
Full–duplex — A high performance protocol that allows simultaneous
two–way data transmission. For point–to–point applications only.
Half–duplex — A high performance protocol that can be used in
point–to–point and multi–point applications.
Initiator — A node on the DH–485 network capable of acting as a master.
When an initiator has the token it can send messages and request replies from
any node on the DH–485 network. A personal computer running the SLC
500 Advanced Programming Software is an initiator on the data link. The
SLC 5/02 can also be an initiator.
Input Device — A device, such as a push button or a switch, that supplies
signals through input circuits to a programmable controller.
Inrush Current — The temporary surge current produced when a device or
circuit is initially energized.
I/O — Inputs and Outputs
Isolated Link Coupler — The link coupler provides an electrically isolated
network connection for an SLC 500 controller (processor or programming
station). The link couplers connect the daisy–chained DH–485
communication cable.
LED — Light Emitting Diode. Used as status indicator for processor
functions and inputs and outputs.
Manual — typically an acoustically coupled type of modem. The
connection is established by a person on each end of the phone line. They
then insert the handsets into an acoustic coupler to complete the connection.
Maximum Watts — The maximum amount of heat that the module
generates with field power present.
Minimum Load Current — The lowest amount of current the output is
designed to operate at. Operating at or below this value is not reliable.