Elmo HARmonica, HARSFEN0602 - page 104

HARSFEN0602
Byte Number Value Type
0-1:
Variable type for user.
This field does not have any practical
significance.
0 for integer
1 for real Byte
2-3:
Data width – number of hex character of a
single transmitted data item.
4 for short integer,
8 for long integer. Byte
4-7:
Data length –
The actual number of transmitted data
items.
Word
8-11:
Variable time multiplier.
This is the number in which TS must be
multiplied to obtain the basic period of the
recorder.
Depends in the RP[0] value. Word
12-19:
Floating number factor.
Multiply every uploaded data item by this
number in order to convert it to user units,
such as Amperes, or Count/sec.
32 bit Float
number in the
IEEE format.
20 – 20 +
(Data Length)*( Data width) –1 :
Data items.
The oldest record is transmitted first, and
the most recent record is transmitted last.
Words or long
integers,
according to
the Data
Width
Table 8-8: BH – record structure
The transmission of a BH record can be quite long. A record of 2000 long numbers is about
8000 bytes, which take at least 4 seconds to transmit in RS232 in the baud rate of 19200. In
this time,
The user program continues to run normally.
CAN commands are accepted and processed normally.
RS232 commands are accepted and executed normally, but the transmission of the response
to them is deferred until the BH upload completion.
Example
A BH command may return the string
0008000100013f80000000010000
This string is decomposed to field as follows:
00 (int) 08 (8 bytes per data item in the message)
0001 (Only one data item in message, after the 20 bytes overhead)
0001 (Record taken every TS)
3f800000 (To scale, multiply result by 1.0. The floating point IEEE representation of 1.0 is
0x3f800000)
00010000 (1st Data item: 0x10000 = 65536)