semi合集-English.pdf - 第1066页

SEMI E5-1104 © SEMI 1982, 2004 8 9.4.3 Encoding C odes from 15 to 327 6 7 are res erved for future e xpansion. Enc oding codes from 32768 t o 65535 are available for custom purposes. 9.5 Example D ata Structures — The da…

100%1 / 7923
SEMI E5-1104 © SEMI 1982, 2004 7
signed integer, codes 30, 31, 32, 34 (octal); floating
point, codes 40, 44 (octal); and unsigned integer, codes
50, 51, 52, 54 (octal). These formats are used for
groups of data which have the same representation in
order to save repeated item headers. In signed integers,
negative values will be two’s complement values.
Floating point numbers will conform to the IEEE
standard 754. Boolean values will be byte quantities,
with zero being equivalent to false, and non-zero being
equivalent to true.
9.3 List — A list is an ordered set of elements, where
an element can be either an item (Section 9.2) or a list.
The list header (LH) has the same form as an item
header with format type 0. However, the length bytes
refer to the number of elements in the list rather than to
the number of bytes. The list structure allows grouping
items of related information which may have different
formats into a useful structure.
9.3.1 A zero-length in the format byte is illegal and
produces an error. A zero-length in the list length bytes
has a special meaning, which is defined in the detailed
message definitions.
Table 1 Item Format Codes
Format Code
(Bit 876543)
Meaning
Binary Octal Data after the heading has the following
form
000000 00 LIST (length in elements)
001000 10 Binary
001001 11 Boolean
010000 20 ASCII
1
010001 21 JIS-8
010010 22 2-byte character
2, 4
011000 30 8-byte integer (signed)
2
011001 31 1-byte integer (signed)
011010 32 2-byte integer (signed)
2
011100 34 4-byte integer (signed)
2
100000 40 8-byte floating point
3
100100 44 4-byte floating point
3
101000 50 8-byte integer (unsigned)
2
101001 51 1-byte integer (unsigned)
101010 52 2-byte integer (unsigned)
2
101100 54 4-byte integer (unsigned)
2
1
Non-printing characters are equipment-specific.
2
Most significant byte sent first.
3
IEEE 754. The byte containing the sign bit is sent first.
4
The code for Multi-byte character must be specified in the data in
the first 2 bytes of the TEXT item.
NOTE: Changes in integer format codes may conflict with earlier
implementations.
9.4 Localized Character String Items — A localized
character string is an item which is used for repre-
senting a string of multi-byte characters. Because there
are many different encoding schemes and the informa-
tion could be in any one of a number of languages,
these characteristics must also be included in the item.
Thus for localized character strings which use item
format code 22 (octal), there is an additional localized
string header (LSH) .
9.4.1 This localized string header follows the item
header and precedes the string. The localized string
header is part of the item data, thus the length of the
header (2 bytes) is included in the length in the item
header. The length of the localized string itself is the
number of bytes that it occupies, regardless of the
number of characters that represents the string. The
localized string header followed by the string together
comprise the localized string item. For example, a 2
byte localized string (which may represent a single
character), because of the 2 byte length of the localized
string header, will have a 4 byte length in the item
header.
9.4.2 The LSH is a 16 bit number which specifies the
encoding method used for the string. Defined values
for the encoding are as follows:
Table 2
Encoding
Code
(Decimal)
Encoding Scheme Notes
0 none reserved
1 ISO 10646 UCS-2 Unicode 2.0
2 UTF-8 Transformation of
ISO 10646 UCS-2
3 ISO 646-1991 ASCII, 7-bit
4 ISO 8859-1 ISO Latin-1,
Western Europe
5 ISO 8859-11 (proposed) Thai
6 TIS 620 Thai (will be
supported by ISO
8859-11)
7 IS 13194 (1991) ISCII
8 Shift JIS
9 Japanese EUC-JP
10 Korean EUC-KR
11 Simplified Chinese GB
12 Simplified Chinese EUC-
CN
13 Traditional Chinese Big5
14 Traditional Chinese EUC-
TW
SEMI E5-1104 © SEMI 1982, 2004 8
9.4.3 Encoding Codes from 15 to 32767 are reserved
for future expansion. Encoding codes from 32768 to
65535 are available for custom purposes.
9.5 Example Data Structures — The data structures for different types of items are illustrated in the following
examples:
a. An item contains one binary code 10101010.
bit
87654321
00100001 Item, binary, 1 length byte
00000001 1 byte long
10101010 data byte
b. An item contains three ASCII characters ABC.
01000001 Item ASCII, 1 length byte
00000011 Three bytes long
01000001 ASCII A
01000010 ASCII B
01000011 ASCII C
c. An item contains three binary numbers in 2-byte signed integer form.
01101001 Item, 2-byte integers
00000110 6 bytes total (6/2 = 3 integers)
xxxxxxxx MSByte number x
xxxxxxxx LSByte number x
yyyyyyyy MSByte number y
yyyyyyyy LSByte number y
zzzzzzzz MSByte number z
zzzzzzzz LSByte number z
d. An item contains one 4-byte IEEE floating point number.
10010001 Item, 4-byte floating point
00000100 4 bytes (4/4 = 1 number)
ffffffff
ffffffff Floating point number
ffffffff in IEEE 754
ffffffff
SEMI E5-1104 © SEMI 1982, 2004 9
e. A message is sent from device 66 telling the host that the temperature at point T1 has exceeded a preset
process limit. The message ID is stream 5, function 1, and the data consists of a list of three items. The first item is
a code for the alarm set and the alarm category code. The second item is the equipment-specific alarm number for
this alarm (e.g., 17). The third item is a string of text giving a brief description of the alarm (e.g., “T1 HIGH.”) No
reply is requested. The complete message including the header is as follows:
10000000 R = 1 (to the host)
01000010 Device Code = 66
00000101 Stream 5, W = 0
00000001 Function 1
10000000 E = 1
00000001 Block 1
00000000
00000000 System bytes = 0
00000000
00000000
00000001 List
00000011 3 Elements
00100001 Binary Item next byte length
00000001 1 byte long
00000100 Alarm set, category 4
01100101 Item, 1-byte integer, next byte length
00000001 1 byte long
00010001 Alarm 17
01000001 Item, ASCII, next byte length
00000111 7 characters
01010100 ASCII T
00110001 ASCII 1
00100000 ASCII space
01001000 ASCII H
01001001 ASCII I
01000111 ASCII G
01001000 ASCII H
9.5.1 Using E4 SECS-I transmission, the entire message contains 1-byte length (not shown), 10 bytes of header, 17
bytes of data, and 2 bytes checksum (not shown) for a total of 30 bytes. At 9600 baud transmission, the message
would be sent in 31 milliseconds.
9.6 Data Item Dictionary — This section defines the data items used in the standard SECS-II messages described in
Section 10, Message Detail.
Name: A unique mnemonic name for this data item. This name is used in message definitions.
Format: The allowable item format codes which can be used for this standard data item. Item format codes are
shown in octal, as described in Table 1, Item Format Codes. The notation “3()” indicates any of the signed integer
formats (30, 31, 32, 34). The notation “4()” indicates any of the floating point formats (40, 44). The notation “5()”
indicates any of the unsigned integer formats (50, 51, 52, 54). The notation “0” indicates that a list with user-
defined structure may be used. Where more than one format is shown, a given implementation can use any of the
formats specified.
Description: A description of the data item, with the meanings of specific values.
Where Used: The standard messages in which this data item appears.
Table 3 Data Item Dictionary
Name Format Description Values Where Used
ABS 10 Any binary string
S2F25, F26
ACCESSMODE 51 Load Port Access Mode.
Possible values are:
0 = Manual
1 = Auto
S3F27