Measurement Specialties 9116 Manual Do Utilizador

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Pressure Systems, Inc.                                                                                        Model 9116 User’s Manual 
 
 
 
Page 10 
 
www.PressureSystems.com 
The host and each module must have a unique Ethernet Hardware Address (a.k.a. MAC 
Address)
 and a unique IP Address.  The Ethernet Hardware address is generally fixed (at 
manufacturing time of the Ethernet microprocessor board inside the module).  The Ethernet 
Hardware address is shown on each module’s label.  The Ethernet Intelligent Pressure 
Scanners are capable of supporting various methods for IP address assignment, using either 
the factory default (static IP addressing) or user-configured Static IP addressing or Dynamic IP 
address assignment. Dynamic IP address assignment is through the use of RARP or BOOTP 
protocols.  Unless your application requires the use of Dynamic IP address assignments, it is 
strongly suggested that the module be left configured for the Static IP address protocol.
  This 
default method is typically the simplest method for using the Intelligent Pressure 
Scanner.  
 
 
In the Static IP addressing mode, the module will use a factory default IP address on power-up.  
This default address is set to 200.20x.yyy.zzz where x is derived from the module type (0 for 
Model 9116 and 1 for 9021/9022) and yyy.zzz is derived from the module serial number.  A 
similar method is used to calculate each module’s Ethernet hardware address shown on the 
module tag.  Note that each of these fields (separated by a period, ‘.’) is a decimal 
representation of a byte value.  This means that each field may have a maximum value of 255.  
For Model 9116 modules,  the default IP address will be 200.200.y.zzz where y and zzz are 
calculated as follows: 
 
y is the integer result of dividing the module serial number by 256. 
zzz is the remainder of dividing the serial number by 256 (serial number modulus 256). 
 
These calculations may be verified by checking that y * 256 + zzz equals the original module 
serial number.  Once a module has powered-up and has assigned itself a default IP address, it 
is capable of communications. 
 
An alternate method for assigning an IP address to an Ethernet module is referred to as a 
Dynamic IP assignment.  This method allows a module to have its IP address dynamically 
assigned at power-up by an application running on a node of the TCP/IP or UDP/IP network.  
When configured for Dynamic IP address assignment protocols, the reset module will broadcast 
its Ethernet hardware (MAC) address on the network in a Dynamic IP request packet.  This 
broadcast packet identifies the module by its hardware address and requests that a dynamic IP 
server application return to it an IP address for use.  Once this broadcast message is received, 
the dynamic server application will then return an IP address to the module in a dynamic IP 
reply packet.  Most dynamic IP server applications determine this IP address from a user 
maintained file that lists Ethernet hardware addresses with their desired IP address.  If modules 
are added to the network or module IP addresses are to be changed, the user can simply edit 
this configuration file.  This capability is common on most UNIX based machines and is also 
available (although less common) in some TCP/IP packages available for PC platforms. 
 
Support of the Dynamic IP server protocol is not currently included in the Windows
®
 95/98/XP or 
Windows
®
 NT operating systems.  In order to allow users of PC platforms to make use of the 
Dynamic IP capabilities of the Model 9116, a simple Windows
®
 95/98/XP/NT application was 
developed by Pressure Systems which is capable of acting as a Dynamic IP server.  This 
application is referred to as BOOTP Lite since it actually makes use of the BOOTP protocol that 
closely resembles the Dynamic IP request.  Like traditional dynamic IP servers, this application 
allows the user to configure a file that contains Ethernet hardware addresses and the 
corresponding IP address to assign to those devices.  This application is free of charge and 
capable of running as a background program on Windows
®
 95/98 and NT machines. It may be 
downloaded from the PSI home page, www.PressureSystems.com.