Burkert Type SE56 - Manual (Page 50)

TECHNICAL MANUAL Rev. Pagine 50/52
Filling By Checked By
03 PROFIBUS DP MODULE- DATA LINK
DESCRIPTION
Document Data Date Date
File name ProfibusDP_emanual_Burkert_04.doc 19/03/08 19/03/08 19/03/08
50
Acyclic Index Write = 101(dec) Setting the value of the High Warning Threshold for the Flow
rate Control with Diagnostic and Alarm
bytes 0-3: High Warning Threshold (32 bit single precision IEEE floating point, MSB first) Flow rate in
technical unit
Acyclic Index Write = 102(dec) Setting the value of the Low Warning Threshold for the Flow
rate Control with Diagnostic and Alarm
bytes 0-3: Low Warning Threshold (32 bit single precision IEEE floating point, MSB first) Flow rate in
technical unit
Acyclic Index Write = 103(dec) Setting the value of the Low Alarm Threshold for the Flow rate
Control with Diagnostic and Alarm
bytes 0-3: Low Alarm Threshold (32 bit single precision IEEE floating point, MSB first) Flow rate in technical
unit
4.1 PROGRAMMING ALGORITHMS
The following algorithms can be applied to IBM™ compatible personal computers. The programs
demonstrated are written in BASIC and are supplied as examples only. The program lines are highlighted in
bold face and the comments are in italics.
4.2 NUMERICAL CONVERSION OF THE DATA RECEIVED
The numerical data contained in the blocks received must be concerted into a format compatible with the PC
format. The arrangement of bytes used to represent numerical values in IBM™ compatible PCs is in fact
inverted with respect to the one in the data received. The following programs illustrate several of the ways
that can be used for these conversions.
We presume that there are bytes to convert in the variable - type Bytes$ string.
· Converting a byte or a group of ASCII characters: no conversion is necessary, the data are already in the
exact order and format.
· Converting a 16 bit signed word: Bytes contains the two bytes that constitute the 16 bit number to
convert. One 16 bit signed word can represent values from -32768 to 32767. The instructions to use may be
the following:
NumIntSgn%=CVI(MID$(Bytes$,2,1)+MID$(Bytes$,1,1))
· Converting a 16 bit unsigned word: Bytes contains the two bytes that constitute the 16 bit number to
convert. One 16 bit unsigned word can represent values from 0 to 65535. Not all BASIC versions can
correctly manage this type of variable; we therefore recommend assigning the converted value to a long
integer 32 bit type variable or to a single precision floating point. The instructions to use (for the long
integer) are:
NumInt&=CVL(MID$(Bytes$,2,1)+MID$(Bytes$,1,1)+ CHR$(0)+CHR$(0))
· Converting a 32 bit long integer: Bytes contains the four bytes that constitute the 32 bit number to convert.
A 32 bit integer may represent values from -2147483648 to 2147483647. The instructions to use may be the
following:
NumInt&=CVL(MID$(Bytes$,4,1)+MID$(Bytes$,3,1)+MID$(Bytes$,2,1)+MID$(Bytes$,1,1))