Plc Handshaking Procedure For Parameter Read/Write - Siemens SINAMICS PERFECT HARMONY GH180 Function Manual

E.4

PLC handshaking procedure for parameter read/write

Register Setup
Use the following procedure to enter and change parameter data in PTD and PFD registers:
1. Write the register data into PTD3 and PTD4 for commands that require PLC data.
2. Write the parameter ID into the PTD2 register.
3. Poll until PFD2 register value equals PTD2 register value (menu ID echo).
4. Write the command type into the PTD1 register.
5. Perform handshake: Poll until the lower 7 bits (0-6) in the PFD1 register are equal to the
value in the PTD1 register (command echo).
6. Error testing:
– Test bit 7 of PFD1 (command echo flag).
– If bit 7 is set, the upper byte of PFD1 is the error code.
– If bit 7 is clear, the upper byte of PFD1 contains the 4-bit exponent for the data if the
7. Read data: Read register data in PFD3 and PFD4 (commands that return PCD data).
8. End the command: Write zero into the PTD1 register (reset the command).
Example: Changing Parameter 'Rated input voltage' (2010)
To change parameter 'Rated input voltage' (2010) to 3000, proceed as follows:
1. Write 3000 to PTD3. This is the new voltage.
PTD4 is not needed.
2. Write 2010 to PTD2. This is the parameter ID for rated input voltage.
3. Poll PFD2 until its value equals 2010 (the value of PTD2).
4. Write 22 to PTD1. This is the Write Parameter Value command.
5. Poll bits 0 to 6 of PTD1 until the value equals 22 (the value of PTD1).
6. When PFD2 equals PTD2 and the lower 6 bits of PFD1 equal PTD1, test bit 7 of PFD1.
– If bit 7 of PFD1 is not set, read bits 8 to 11 for the exponent.
– If bit 7 of PFD1 is set, read bits 8 to 15 for the error code.
7. Read PFD3 and PFD4 for the new value.
8. Write 0 to PTD1.
NXGpro Communication
Function Manual, AB, A5E33486415A
command was "Read Parameter Value." For all other commands, the upper byte is zero.
E.4 PLC handshaking procedure for parameter read/write
Parameter Read/Write
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