User Guide

FS-8700-86 Carrier DataPort Page 19 of 32
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Appendix A.3. Map Descriptor Length Explained
The Length parameter is specified as part of the Map Descriptor.
Client Reads:
The length means: “The number of table variable’s whose values are to be stored when the response
is received.” If you do not know the length of the table in advance, set the length to a larger number
(e.g. 100). The driver will process the response; if the table contains more than 100 elements then
some data will be discarded.
Server:
The length parameter is used when the server returns a value that is a string. The length is used to
tell the driver how many characters to extract from consecutive array location to form the response
string. When the server returns a value that is a number, state or time the length should always be 1.
Appendix A.4. How the Client stores the states/values of the Table Variables.
Appendix A.4.1. Discrete States
When a Carrier DataPort device reports the state of a table variable which has a discrete state, it
reports the state as a keyword like on/off. This driver converts the keywords to facilitate reading
by other devices.
The driver is programmed to recognize the keywords listed below. The user can add keywords
by specifying additional information in the configuration file.
State Word Value State Word Value State Word Value
CLEAN 1 ABNORMAL 1 OPEN 1
DIRTY 0 NORMAL 0 CLOSE 0
HEAT 1 LOCAL 0 CLOSED 0
COOL 0 REMOTE 1 ALARM 1
ON 1 LOCAL R 0
OFF 0 RUNNING 1
If the driver doesn’t recognize the state word, it stores the characters of the state word as decimal
values based on their ASCII value. the number of characters stored is dependent on the length
parameter.
For example, say the driver responds, reporting a variable to be a state ‘INCREDIBLE’. If the
length parameter of the polling Map Descriptor is 1 then the driver stores the first character of the
word incredible; by storing a value of 73 (An uppercase ‘I’ is the seventy third character in the
ASCII alphabet.).
The driver recognizes discrete state words by checking the 1
st
character of the value field. If it is a
non-digit then it is regarded as a state word. The comparison against keywords in the list is done
without respect for the case of the letters.
Unrecognized Discrete State Words
If the driver does not recognize the discrete state word that has been used it will report the
following error - CarrDP:#24 Err. MD=<MapDesc1> discrete state word not recognized.
The unrecognized discrete word can be found by extracting 10 characters from the line starting at
the 10th character. Once the 10 characters have been extracted they are left and right trimmed
to remove leading and trailing spaces.