Welch-allyn SureTemp PlusModule - User Manual Instrukcja Użytkownika Pobierz pdf (Strona 55)

SureTemp Plus Module OEM Implementation Communications Protocol

Welch Allyn OEM Technologies Conﬁdential 55

Command and Response Strings: Examples

This section provides examples of command and response strings for some of the more

commonly used commands. It also provides a brief description, with examples, of endianness.

Endianness

Big-Endian Numbers

In big-endian machines—typical of Motorola® processors—the high-order byte is ﬁrst:

Command Code (Word): 0x94 0x1C = 0x941C

Little-Endian Numbers

In little-endian machines—typical of Intel® processors—the low-order byte is ﬁrst:

Byte Count (Word): 0x13 0x00 = 0x0013.

In IEEE 754 little-endian ﬂoating-point numbers, the least-signiﬁcant byte is ﬁrst:

IEEE 754 Data Format

The IEEE 754 ﬂoating-point data format consists of four contiguous bytes: a 23-bit signed binary

mantissa and an 8-bit biased binary exponent:

Converting a String of Bytes to a Floating-Point Number

1. Swap the bytes to the endian format used by processor on which the software is running.

2. In C, cast the number to a ﬂoat

Decimal Hexadecimal

100.0 00 00 C8 42

-100.0 00 00 C8 C2

0.5 00 00 00 3F

-1.75 00 00 E0 BF

0.56 29 5C 0F 3F

0.0625 00 00 80 3D

Bits Description

0 Sign of the mantissa (0 = positive; 1 = negative)

1 - 8 Exponent (8-bit unsigned value)

(The implied binary point is between bits 8 and 9.)

9 - 31 Mantissa

1 2 ... 50 51 52 53 54 55 56 57 58 59 60 ... 84 85

Brak uwag

Welch-allyn SureTemp PlusModule - User Manual Instrukcja Użytkownika Strona 55