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12/2/2011 4:48 PM | |
Posts: 344 Rating: (50)
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I looked at the documentation and for CU240S looks like the only speed reference option is frequency: Hz and not rpm. However, the setpoint and actual frequency in all SINAMMICS drives is a real number. When sending and receiving data on Profibus (WORD or DWORD), the drive automatically scales the value to use the full 16 or 32 bit resolution (depending on the telegram selected) available. Parameter 2000 defines the reference frequency value. See description in the Sinamics G120 Parameter manual. For example, when the motor operates at 60Hz, the drive will send a value of 16,384 (4000 HEX) to the PLC/HMI if P2000 = 60.0. The PLC will need to convert that number from integer value back to real frequency or rpm value. Theoretically, you could have manipulated P2000 so the integer value on the Profibus represents rpm. It would require reference frequency to be set at 3,600 Hz, but the P2000 value is limited to 650Hz. So, looks like the PLC must scale the speed value in either case. The good news is that resolution is a lot higher the 1Hz. |
Last edited by: DenisMor at: 12/2/2011 4:49 PMLast edited by: DenisMor at: 12/2/2011 4:49 PM |
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