102 • Appendix B - Profibus
Step 1: Find the register numbers
In this document, we will use a simple PROFIBUS master tool to demonstrate how to change parameters.
This tool is very simple and it allows you to modify the parameters only by writing the hex numbers.
Go to the table in section
B.4 and find the register number for each register. The tool used in our example requires
the hexadecimal value so we also need to convert the register number into its hex equivalent.
The following table shows the register numbers for the registers used in our example.
Register name Decimal number Hex number
Logic Status 1 00 01
Motor Current 2 00 02
Line Voltage 3 00 03
Hardwired inputs 5 00 05
Thermistor Resistance 11 00 0B
Thermal Capacity 37 00 25
Frequency 10 00 0A
Phase Sequence 4 00 04
DIP switch 9 00 09
Elapsed Run Time 18 00 12
Step 2: Update the register numbers
Write the following to slot number 1 and index number 2 using Data Request (DPV1).
B.1.3. Read and Write from Random Registers via Data Request
Reading or writing by Data Request (DPV1) allows you to read or write up to 20 registers in a single request.
In order to read or write via Data Request (DPV1) you need to perform 2 operations:
• First update the first register number that we want to read or write.
• Second read or write the register.
Configure the first register number by writing to slot number 2 and index number 2.
The length of the register number must always contain two bytes (word). If we want to read from register number 5
we need to read from register number 0x0005. The first byte is the high part of the number (the MSB).
To read or write multiple registers, we need to define the number of the words that we want to read or write.
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