Modbus Rtu Indirect Parameter Access - Invertek Drives Optidrive iE3 Technical Manual

4.7.11 Display Scaling (P-40)
The parameter value is stored as a combined 16 bit word which is constructed as follows:-
High Byte
15 14
Display Scaling Source
0: Motor Speed
1: Motor Current
2: Analog Input 2 Signal
3: PI Feedback
4.8

Modbus RTU Indirect Parameter Access

Optidrive E3 allows Read / Write access to all user adjustable parameters using a simple method as detailed below. This is achieved using the
following two Modbus registers.
4.8.1.1 Register 44: Drive parameter index
This index value will be used by register 45 to carry out parameter read and write function. The valid range of this parameter is from 1 to 60
(maximum number of drive user adjustable parameters)
4.8.1.2 Register 45: Drive parameter value
When reading this register, the value represents the drive parameter value which index is specified by register 44.
When writing to this register, the value will be written to the drive parameter number specified by register 44.
4.8.2 Parameter Read Method
In order to read a parameter, firstly write the parameter number to register 44, then read the value from register 45, e.g. to Read the Value of
P-01

Write 1 to Register 44

Read the Value of Register 45
4.8.3 Parameter Write Method
Writing parameter values can be achieved by the same method, however Register 45 is used to write the parameter value after the parameter
number has been selected using Register 44, e.g. to Write a Value of 60.0Hz to parameter P-01

Write 1 to Register 44

Register 45 will return the present value of P-01, which can be Read if required

Referring to the parameter table shown in 4.6.2, apply any scaling necessary
o
In this case, 60.0Hz = 3600

Write the scaled value to Register 45. P-01 now changes to 60.0Hz, or an exception code may be returned.
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Optidrive E3 Advanced Technical Manual Issue 05.Docx
Low Byte
13 12 11 10 9 8 7
Display Scaling Factor: 3dp, e.g. 0 – 16000 = 0.000 – 16.000
6 5 4 3 2 1 0