Glossary
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Channel In an S901 I/O subsystem, a group of 128 inputs and 128 outputs assigned to a
segment. The ladder logic in the segment usually controls all I/O operations of the
corresponding channel.
Characters per
Inch (CPI) The number of characters a printer prints in one inch. (Also called horizontal pitch.)
Checksum A calculation that sums a range of data and compares it to a pre-calculated value.
This determines if the data is in error or has changed.
Coaxial Cable A round cable containing two conductors, one inside the other (separated by a
insulator). The inner conductor transmits a signal while the outer conductor is a
shield.
Commentary The descriptors, short comments, long comments, and page titles within a project.
Controller An industrial control computer, also called a programmable logic controller or PLC.
CPS Characters per Second.
Cross-Reference A list of the networks in which a particular address can be found.
Current Element The cell or ladder logic element being edited. The logic editor’s cursor is always on
the current element.
Current Network The network being edited. The network displayed in the logic editor is always the
current network.
Cursor A bar or block which indicates a position on the screen. Generally, the cursor is
located where something can be inserted or selected.
Data Bits The bits in a data package which carry a message, distinct from start bits, stop bits,
and parity bits. Remote Terminal Unit mode (the Modbus default communication
mode) sends eight data bits per package. ASCII mode sends seven data bits per
package.
Data Contents A printout showing the data values in a ladder logic program.
Data Register A 4xxxx holding/output register.
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