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User Guide
4
Profibus DP Operation
This section gives details of how to apply the LMP to a Profibus DP System.
It does not go into detail explaining Profibus DP. Further information can be
found by visiting the designated website: www.profibus.com
When the LMP processor is connected to a Land System 4 thermometer, the
processor must be configured for use with that particular thermometer type.
Profibus DP uses a '.gsd' file as an electronic data sheet to allow the master
processor to set up the operating parameters for the slave units attached to
it's network.
4.1 .gsd Files
The Landmark for Profibus (LMP) is registered with the Profibus Nutzer
Organisation (PNO) and has been designated with the special register
number: LAND 0807.
A .gsd file has also been allocated to this registration and is supplied on disk,
with the processor. (LAND 0807.gsd).
To allow access to the user parameters and cyclic data configuration of the
processor, this .gsd file must be copied from the supplied disk to the gsd
directory of the master system in use.
4.2 User Parameters
User parameters are downloaded from the master system to the LMP, as a
one-off at the start of Profibus operation. These user parameters are stored
in a non-volatile memory within the LMP (if the LMP should lose power AND
Profibus connection, the last set of user parameters would be reverted to, the
next time that the system is switched on, until a new set of user parameters
are downloaded).
The .gsd file uses 'revision2' options to allow 'Help' texts when setting user
parameters.
Modern Profibus DP master systems utilise this option to greatly assist in the
setting of user parameters, which are usually selected through dialog boxes.
The dialog boxes allow the translation of the parameter indices, they offer
default values and include built-in limits for most parameters (except for
limits that depend on the 'irt' type). The screen layout varies from master to
master.
Older master systems are not compatible with the configuration as above.
They ignore the 'revision2' commands in the .gsd file and offer a list of user
parameter bytes which require editing. The order of the user parameter bytes
is very important and must be strictly followed. (See Table 3)
Landmark for Profibus
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