Owner's manual

4. SECS Message Detail
This section describes the basics of SML notation and lists each message sent or understood by
the Equipment.
4.1 SML Notation
Message descriptions are shown using “SECS Message Language” (SML) notation. SML is a general
notation developed by GW Associates for describing SECS messages. SML is similar to the notation used
in the SECS Standards documents, but SML is a more precise and regular notation.
4.1.1 Data Item Format
In SML, the format for a Data Item is as follows:
< type [ count] value >
The components of a Data Item are listed and described in Table 4-1.
Table 4-1 Components of a SML Data Item
Component Description
< >
Angle Brackets. Each Data Item is enclosed within angle brackets (“less than”, “greater
than”). This notation implies that each Data Item has a Data Item Format and Data
Item Length as required by SECS-II.
type
This specifies the SECS-II Data Item format. It will have one of the following values:
A ASCII
B Binary
J JIS-8
I1, I2, I4, I8 Signed Integers
U1, U2, U4, U8 Unsigned Integers
F4, F8 Floating Point
BOOLEAN True/False
count
Count of the element values that make up the item. If present, the count is enclosed
within square brackets “[ ]”. The count may be omitted, in which case the square
brackets are also omitted.
The “count” specifies the number of value elements in the Data Item Value. For String
formats (ASCII, Binary, JIS-8), “count” specifies the number of characters in the string.
For Numeric formats (I1, I2, I4, I8, U1, U2, U4, U8, F4, F8, BOOLEAN), “count”
specifies the number of values in the array. For simple scalar numeric values, “count”
is usually “1”. For LIST items, “count” specifies the number of items in the list.
If “count” is omitted, then the length of the Data Item is implied by the value which
follows. The “count” can range between known limits. It may be specified as minimum
and maximum “counts”, separated by two dots. (For example, [0..40]).
Equipment-to-Host Messages 4-1