C-Link Protocol Commands
Record Layout Definition
B-42 Model 48i Instruction Manual Thermo Electron Corporation
The value field displays values which are parsed out of the response to a
DATA/ERec command. It also displays, though background changes, alarm
status. The button, when pressed, triggers input from either a dialog box or
a selection list. There are five kinds of buttons, B, I, L, T, and N.
Each line in the layout string corresponds to one line on the display. The
layout string describes each of the three major fields as well as translation
mechanisms and corresponding commands.
Text The first field in the layout string is the text. It is delimited by a ':'. The
string up to the first ':' will be read and inserted in the text field of the line.
Value String This is followed by a possible string, enclosed in quotes. This is used to place
a string into the value field.
Value Source The value source, which is the item (or word) number in the DATA/ERec
response, appears next. This is followed by an optional bitfield designator.
The datum identified by the value source can be printed as a string 's',
hexadecimal 'x', decimal 'd', or floating point 'f', or binary 'b' number.
Typically, bitfield extractions are only done for decimal or hexadecimal
numbers.
Floating-point numbers can be followed with an optional precision specifier
which will be used as an argument to printf's %f format (e.g., a field of '4'
would be translated into the printf command of '%.3f'). Alternately, the
special character '*' can precede the precision specifier; this causes an
indirection on the precision specifier (which now becomes a field number).
This is useful when formatting, for example, numbers which have varying
precision depending on the mode of the instrument.
Binary numbers can also have an optional precision specifier which is used
to determine how many bits to print. For example, the specifier 'b4' will
print the lowest four bits of the parsed number.
There are serious restrictions on where an 's' field may appear: currently
sources 1 and 2 must be 's', and no others may be 's'.
Alarm Information The value source is followed by optional alarm information, indicated by a
commercial at sign '@' with a source indicator and a starting bit indicator.
All alarm information is presumed to be two bits long (low and high). The
bitfield extraction is performed on the integer part of the source. Typical
alarm information would appear as '@6.4'.
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