Parameter Generation and Control 9354-4250, Инструкция по установке и эксплуатации

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PGC, Inc. Appendix B; SmartPad version 0.503 Steady State & Programmable
November 2005 B-29
IV. TYPES OF COMMANDS:
The SmartPad™ will respond to two types of commands; requests and inputs. A request is a
command that instructs the SmartPad™ to return a value to the terminal. An example of this is if
the terminal were to request the current measured air temperature. An input is a command that
instructs the SmartPad™ to accept the following data. For instance, if the terminal were to give
the SmartPad™ a new air set point.
All commands are preceded by either a “?” for a Request or an “=” for an input. This is
followed by a three-character command. A data string can follow inputs. Spaces, (<SP>) are
required between the command and the data string, as well as between each individual data field,
if more than one exists. Decimals and colons may be omitted or used if preferred. All
commands must be followed by a carriage return. (<CR>). Uppercase and lowercase letters are
equally valid. It is important to note that all data entered into the SmartPad™ is stored in non-
volatile memory (EEProm). This type of memory has a finite limit to the number of write/erase
cycles. This limit is vaguely in the 5-10,000-cycle range. This should more than exceed the life
of the device for standard keyboard driven data entry. If, however, an automatic set point entry
scheme is used the EEProm could easily be destroyed much faster. An example of this would be
to develop a ramping controller driven by a remote terminal. This situation should be avoided.
Portions of the command line are optional. The required portion is listed in Bold type. When
entering a numeric value, the delimiters (decimal points or colons) are optional.
Example:
To request the current Air Set point.
?AS is the same command as ?AS p
?A is not the same command as ?AS p or ?AS