Selectron LD-007 Manual de Instruções descarregar pdf (Página 359)

Glossary

359

set The process of turning a bit or signal ON.

set value The value from which a decrementing counter starts counting down or to

which an incrementing counter counts up (i.e., the maximum count), or the

time from which or for which a timer starts timing. Set value is abbreviated

SV.

shift register One or more words in which data is shifted a specified number of units to the

right or left in bit, digit, or word units. In a rotate register, data shifted out one

end is shifted back into the other end. In other shift registers, new data (ei-

ther specified data, zero(s) or one(s)) is shifted into one end and the data

shifted out at the other end is lost.

Slave Short for Remote I/O Slave Unit.

Slave Rack A Rack containing a Remote I/O Slave Unit and controlled through a Remote

I/O Master Unit. Slave Racks are generally located away from the CPU Rack.

slot A position on a Rack (Backplane) to which a Unit can be mounted.

software error An error that originates in a software program.

software protect A means of protecting data from being changed that uses software as op-

posed to a physical switch or other hardware setting.

source The location from which data is taken for use in an instruction, as opposed to

the location to which the result of an instruction is to be written. The latter is

called the destination.

Special I/O Unit A dedicated Unit that is designed for a specific purpose. Special I/O Units

include Position Control Units, High-Speed Counter Units, Analog I/O Units,

etc.

SR area A data area in a PC used mainly for flags, control bits, and other information

provided about PC operation. The status of only certain SR bits may be con-

trolled by the operator, i.e., most SR bits can only be read.

subroutine A group of instructions placed after the main program and executed only if

called from the main program or activated by an interrupt.

subroutine number A definer used to identify the subroutine that a subroutine call or interrupt

activates.

SV Abbreviation for set value.

switching capacity The maximum voltage/current that a relay can safely switch on and off.

syntax error An error in the way in which a program is written. Syntax errors can include

‘spelling’ mistakes (i.e., a function code that does not exist), mistakes in

specifying operands within acceptable parameters (e.g., specifying reserved

SR bits as a destination), and mistakes in actual application of instructions

(e.g., a call to a subroutine that does not exist).

system configuration The arrangement in which Units in a system are connected.

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Selectron LD-007 Manual de Instruções Página 359