Glossary
318 372 SPU 780 01EMAN May 2002
Run Light A light on the front panel of a controller that is on while the controller is running.
Save To store information on a disk.
Search To locate a specified network element (or elements) in the ladder logic.
Segment A group of I/O networks solved as a unit by the programmable controller. The
Segment Scheduler controls the frequency of segment execution and order of I/O
operations. Each segment controls two I/O channels in a 584 or 984/S901
configuration, or one drop in a 984/S908 configuration.
Serial Port A 9- or 25- pin port used for serial communications (for example, Modbus).
Short Comment Up to four lines of text which comprise a comment about an address within a PLC
ladder logic program. Typically printed beside output instructions in the ladder
listing.
Short Comment
Field One of up to four lines of text which comprise a comment about an address within a
PLC network logic program. Typically printed beside output instructions, or below
the network in the network listing.
Slave A networked device controlled by another device. Slave devices to not initiate data
transactions. Compare to Master.
Slot The position of an I/O module in a rack.
State Flow In logic, an instruction is highlighted if it solves true instead of only when it passes
power (compare to Power Flow).
Stop Bits Bits used to indicate the end of transmission of a data item or frame.
Subdirectory A directory within a directory.
Sweep For a PLC, one cycle of scanning inputs, solving logic, and writing outputs.
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