Hardy HI 4050, User Manual

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Configuration 71
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PROFIBUS
®
Configuration
ProfiBus DP operates using a cyclic transfer of data between master(s) and slave(s) on an
RS485 network. An assigned master periodically requests (polls) each node (slave) on the
network. The HI 4050 is a slave device. All data communication exchanges between a
master and the HI 4050 originate from the master device. Each HI 4050 is assigned to one
master and only that master may write output data to that HI 4050. Other masters may read
information from any slave, but can only write output data to their own assigned slaves.
Because ProfiBus uses a cyclic (periodic) polling mechanism between masters and slaves,
it is also deterministic. Therefore behavior of a ProfiBus system can be reliably predicted
over time. ProfiBus is designed to guarantee a deterministic response.
The length (and timing) of the I/O data to be transferred from a single slave to a master is
predefined in the slave's device data base or GSD file. The GSD files of each device
connected via the network (slaves and class 1 masters only) are compiled into a master
parameter record which contains parameterization and configuration data, an address
allocation list, and the bus parameters for all connected stations. A master uses this
information to set up communication with each slave during startup. Slaves can only
acknowledge the messages they receive or transfer messages to a master when the latter
requests a slave to do so. Slaves are also designated as passive nodes.
Configuring PROFIBUS From the Web Interface
Step 1. From the Configuration menu select Options to open the Options menu; then
Click on Profibus Card. to open the Click on Profibus Card form.
Double click in the Node text field to highlight the current entry.Type in the HI 4050 Node
address.
Range: 1-125 (default 5) Our example uses the default address #5.
NOTE PROFIBUS Node Address #5 is the lowest number that can be used by a slave device.
Step 2. Click Save Parameters to save the entry.
Step 3. You can also read the communication status of the instrument.
Step 4. Click Home to return to the Home Page.