Elmo HARmonica, HARSFEN0602 software manual Preliminary Draft, Byte Number Value Type

HARSFEN0602ElmoHARmonicaSoftwareManual		PRELIMINARY	DRAFT
				102
	Byte Number	Value	Type
	0-1:	0 for integer	Byte
	Variable type for user.	1 for real
	This field does not have any practical
	significance.
	2-3:	4 for short integer,	Byte
	Data width – number of hex character of a	8 for long integer.
	single transmitted data item.
	4-7:		Word
	Data length –
	The actual number of transmitted data
	items.
	8-11:		Word
	Variable time multiplier.	Depends in the RP[0] value.
	This is the number in which TS must be
	multiplied to obtain the basic period of the
	recorder.
	12-19:		32 bit Float
	Floating number factor.		number in the
	Multiply every uploaded data item by this		IEEE format.
	number in order to convert it to user units,
	such as Amperes, or Count/sec.
	20 – 20 +		Words or long
	(Data Length)*( Data width) –1 :		integers,
	Data items.		according to
	The oldest record is transmitted first, and		the Data
	the most recent record is transmitted last.		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)