Rockwell Automation 1775-S4B,D17756.5.3 User Manual SCANNER/MSG HND - Manual (Page 162)

Glossary
Appendix D
DĆ4
Modem: Modulator/Demodulator. A data transceiver.
Modem handshaking: A signaling protocol used for
transferring information between devices in a synchronized
manner at a rate acceptable to both devices.
Modifier: A parameter preceded by a slash (/) that follows a
command. It tells the 1775-S4B scanner how to execute the
command.
MSG instruction: A PLC-3 ladder diagram instruction that
sends a message or procedure to a specified RS-232-C port in
the PLC-3 system.
Octal Numbering System: A numbering system that uses a
base eight; for example, the decimal number 324 would be
written in octal notation as 504
8
. Only the digits 0 thru 7 are
used.
Parity: A method of testing the accuracy of inary numbers
used in recorded, transmitted, or received data.There are two
types of parity:
Even parity is a condition that occurs when the sum of the
number of (1s) in a binary word is always even.
Odd parity is a condition that occurs when the sum of the
number of (1s) in a binary word is always odd.
Procedure: A collection of report generation command lines
that the 1775-S4B scanner uses to generate formatted text and
data.
Procedure name: A group of eight alphabetic and/or numeric
characters used to identify a procedure.
Privilege: A resource of the PLC-3 programmable controller.
The user can restrict these resources from external ports such
as the PLC-3 front panel or an RS-232-C port. These resources
include:
Ability to write to major sections of PLC-3 memory
Ability to create, delete, and move sections of PLC-3 memory
Ability to configure the watchdog timer, system clock, and
operating context
Ability to configure the I/O channels and RS-232-C channels