West Control Solutions KS 800 ISO1745 Interface Manual - Manual (Page 8)

3 Message structure
3.1 Message elements
In the following section, some expressions which shall be explained as follows are used:
Element Description Rem.
Address of a participating unit, always 2 bytes long, adjustable on the instruments A
Data field composed of
a) fields a. , separated by character ‘=’
b) a series of successive with several block accesses
B
identification field composed of
a) field and
b) different selection criteria
C
Value of a datum, which is addressed with a key.
Addressing key of a datum, 2-digit, decimal number range, first digit also ‘B’. D
further addressing field for selection of a. E
Block Check Count. All characters between STX (exclusive) and ETX (inclusive) are
connected bytewisely by an EXOR function and output as 1 byte, always after ETX.
F
Bem. A Address field
The adress field can be transmitted only after ‘EOT’ and must be generated only by the master. It is two
bytes long. The address number range is 00 ... 99. If the transmitted address corresponds with the one
adjusted in the unit, the message is intended for this unit.
Different address settings are possible for COM1 and COM2.
Bem. B Data field
The data field contains the parameters and data to be transmitted.
The equality sign is followed by the value of a datum (). Several data are separated by a comma.
The data type depends on the access. The last value before ‘ETX’ ends without ‘,’.
With block read access with additional selection criteria, these criteria are specified only once. The data
follow without further identifications. Thus, the message structure becomes more compact.
Bem. C Identification field
The identification field addesses a defined datum or a data area in the instrument. It consists of a code and of
an additional selection identification with some accesses.
With a data enquiry, the identification field contains information for KS92/94 which data the unit is expected
to send. This is always followed by the address field. In the reply, it is also specified for clear determination
of the datum, followed by the data field with separator „=“.
With data entry, STX is followed by the identification field for addressing the values to be specified.
Connection of the data field is by means of character „=“.
Bem. D Code
The code identification is two bytes long and the value range is ASCII ‘00’...’99’ and ‘B2’... ‘B3’.
Message structure
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