ADwin System with Ethernet Interface
ADwin
62 ADwin Installation, manual version 2.1, December 2005
9.5 Application-specific features
Basically there is no difference wether your application communicates with an
ADwin system via ADwin Ethernet interface or another interface. All programs
access the ADwin system via the ADwin driver (ADwin32.dll).
Configurating the system with the program ADconfig tells the DLL via which
interface the ADwin system is accessed.
If the communication to the ADwin system is made via ethernet (i.e. via ADwin
Ethernet interface), the following items have to be considered:
Data integrity – If the ADwin Ethernet interface is operated with a "cross-over" cable or
an individual network, you will get the highest data integrity and the high-
est data transfer rates.
Collision bus –The ADwin Ethernet drivers are designed for high data integrity. Never-
theless a loss of data packages may rarely occur on the network caused
by multiple collisions (ethernet is a collision bus) or by multiple retries.
Therefore your program should check each time if the communication
with the ADwin system was successful and respond perhaps with a retry
(see also the instruction "GET_LAST_ERROR" in the ADwin driver man-
ual for your development environment).
Response times – The data transfer rates via ethernet can be very high, but the response
times are longer than those of other interfaces. If you have to query
many ADbasic parameters in your program, you definitely ought to use
the following instructions (see also the descriptions in the ADwin driver
manual for your development environment):
GET_PAR_ALL, GET_FPAR_ALL, GET_PAR_BLOCK,
GET_FPAR_BLOCK
These instructions allow the reading of a block of or even all pre-defined
variables from the ADwin system with only one instruction at all.
This means for the communication via Ethernet that you can get a lot of
ADwin variables in approximately the same time as a single ADwin vari-
able.
To Next Page
Loading...