Campbell CR7, Инструкция по эксплуатации

Страница: 159 / 186

A-1
APPENDIX A. GLOSSARY
ASCII: Abbreviation for American Standard
Code for Information Interchange
(pronounced "askee"). A specific binary
code of 128 characters represented by 7 bit
binary numbers.
BAUD RATE: The speed of transmission of
information across a serial interface,
expressed in units of bits per second. For
example, 9600 baud refers to bits being
transmitted (or received) from one piece of
equipment to another at a rate of 9600 bits
per second. Thus, a 7 bit ASCII character
plus parity bit plus 1 stop bit (total 9 bits)
would be transmitted in 9/9600 sec = .94
ms or about 1000 characters/sec. When
communicating via a serial interface, the
baud rate settings of two pieces of
equipment must match each other.
DATA POINT: A data value which is sent to
Final Storage as the result of an Output
Instruction. Strings of data points output at
the same time make up Output Arrays.
EXECUTION INTERVAL: The time interval
between initiating each execution of a given
Program Table. If the Execution Interval is
evenly divisible into 24 hours (86,400
seconds), the Execution Interval will be
synchronized with 24-hour time so that the
table is executed at midnight and every
execution interval thereafter. The table will
be executed for the first time at the first
occurrence of the Execution Interval after
compilation. If the Execution Interval does
not divide evenly into 24 hours, execution
will start on the first even second after
compilation.
EXECUTION TIME: The time that it actually
takes the CR7 to execute an instruction or
group of instructions. If the execution time
of a Program Table exceeds the table's
Execution Interval, the Program Table will
be executed less frequently than
programmed.
FINAL STORAGE: That portion of memory
allocated for storing Output Arrays. Final
Storage may be viewed as a ring memory,
with the newest data being written over the
oldest. Data in Final Storage may be
displayed using the *7 Mode or sent to
various peripherals.
HIGH RESOLUTION: A high resolution data
value has 5 significant digits and may range
in magnitude from ±.00001 to ±99999. A
high resolution data value requires 2 Final
Storage locations (4 bytes). All Input and
Intermediate Storage locations are high
resolution. Output to Final Storage defaults
to low resolution: high resolution output
must be specified by Instruction 78.
INDEXED INPUT LOCATION: An Input
location entered as an instruction parameter
may be indexed by keying "C" before
entering by keying "A", two dashes (--) will
appear at the right of the display. Within a
loop (Instruction 87), this will cause the
location to be incremented each pass
through the loop. Indexing is also used with
Instructions 13, 14 and 75 to cause an Input
location, which normally remains constant,
to be incremented with each repetition.
INPUT/OUTPUT INSTRUCTIONS: These
Instructions tell the I/O Module what to do.
Input/Output Instructions are used to initiate
measurements and store the results in
Input Storage or to set Digital Control Ports
or Continuous Analog Output channels.
INPUT STORAGE: That portion of memory
allocated for storing the results of Input and
Processing Instructions. The values in
Input Storage can be displayed and altered
from the *6 Mode.
INSTRUCTION LOCATION NUMBER: As
instructions are entered in a Program Table
they are numbered sequentially. The
instruction location number is the number
giving an instruction's order in the Program
Table. When programming a table, the
instruction location number and a P (e.g.,
04: P00) prompts the user when it is time to
enter an instruction.