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Measurement Specialties Inc. NetScanner System (9016, 9021, & 9022) User’s Manual

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A “peer” may be directly addressed by its IP address (in xxx.xxx.xxx.xxx format), or by use of a

predefined logical name that allows its IP Address to be looked-up in the sender’s database or in a

central network server’s database. The Windows

95/98/2000/NT operating systems provide a

simple text file database called “Hosts.” Review the file “Hosts.sam” in the “C:\windows”

directory. Modify and rename it “Hosts.” (no file extension) to activate it.

Before the host computer and any module can communicate with the higher level TCP/IP

protocols, the host (client) must request a connection be established with the module (server).

Each module expects all such requests for connection to be requested by its IP Address, and

directed to “well-known” port 9000 (default). After the connection is made, a socket is

established as a logical handle to this connection. The host and module may then communicate,

via this socket, until it is closed or is lost at either module or host end, due to power failure or

reboot). The host and module may also communicate in a limited fashion without a connection,

using the middle-level UDP/IP protocols. In that case, the host simply broadcasts commands via

port 7000, and each module (that chooses to respond) returns the response on port 7001. Only a

few commands use UDP/IP in NetScanner



System modules.

3.1.2 Commands

The commands (and responses) used by Models 9016, 9021, and 9022 modules consist of short

strings of ASCII characters. The TCP/IP and UDP/IP protocols allow for the transfer of either

printable ASCII characters or binary data. When using certain formats, internal binary data values

are often converted to ASCII-hex digit strings externally. Such values may include the ASCII

number characters ‘0’ through ‘9,’ the uppercase ASCII characters ‘A’ through ‘F,’ and the

lowercase letters ‘a’ through ‘f’.’ These hex values may represent bit maps of individual options,

or actual integer or floating point (IEEE) binary data values. In other cases (see optional format 7

below) binary data may be transmitted directly as 4-byte (32-bit) binary values without any

formatting change. Such binary transmissions use big-endian (default) byte ordering but may be

commanded to use little-endian for some data.

3.1.2.1 General Command Format

A typical TCP/IP command (contained in the data field following a TCP packet header) is a

variable-length character string with the following general fields:

• a 1-character command letter (c).

• an optional position field (pppp), a variable length string of hexadecimal digits.

• a variable number of optional datum fields ( dddd): each a variable length string, normally

formatted as a decimal number (with a leading space character, and with or without sign

and/or decimal point, as needed).

Using brackets ( [ ] ) to show optional elements, and ellipsis ( ...) to show indefinite repetition, a

typical TCP/IP command may be viewed schematically as follows:

1 2 ... 30 31 32 33 34 35 36 37 38 39 40 ... 193 194

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Pressure Systems 9022 Manuel d'utilisateur Page 35