How to achieve communication between Siemens 200 SMART and Delta frequency inverters? First, we need the following configuration:
Programming software: S7EDP—MicowiSMART; CPU configuration: ST20 DC/DC/DC.
Inverter B: VFD 007 B 23 A (2hp 1.5KW);
Functions: Control the start and stop of the frequency converter, set the operating frequency of the frequency converter, and read the main operating parameters of the frequency converter, including output frequency, output voltage, and output current.
The procedure is as follows:
Upon power-up, the CPU resets the 16 bits starting from M0.0 and clears the MD2 and VW2 memory areas to 0.
Without using a touchscreen, these data can be monitored through the status table of the programming software during program debugging. In actual use, they can be switched on the inverter display panel, and these parameters can be read intuitively in the function code "00-04" option.
Assign a frequency value to VW2, and connect an external self-reset button. Pressing I0.3 once increases the frequency; pressing I0.4 once decreases the frequency.
Inverter parameter settings:
02-00 Frequency source setting: “04” Input via RS-485 communication;
02-01 Operation command source setting: "04" is communicated via RS-485; the STO key on the interface operation keyboard is invalid.
01-07 Output frequency upper limit 50.00
01-08 Output frequency lower limit 0.00
09—00 Communication Address 01
09—01 Communication transmission speed 02 19200
09-04 Communication Data Format 04 8, E, 1 for RTU
00-04 To view the inverter's operating parameters, you can switch to view them via the operation panel shown in the image below.
The motor parameters are set in the corresponding function codes of the frequency converter according to the information on its nameplate.
Communication protocol address conversion
The driver's command register "2000H" is a 16-bit number. Convert it to a 10-bit number "8192", add the MODBUS address offset bit 1, and it becomes "8193". Add the type number "4" in front, and it becomes 48193.
Data content: For forward operation, the startup content needs to be added, represented in binary, the lower 8 bits are 0001 0010, which is converted to 12 by a 16# converter;
To run in the reverse direction, the startup content must be represented in binary, with the lower 8 bits being 0010 0010, which is converted to 22 using a converter 16#.
Stop at 16#1.
The read/write command register address translation for the drive is the same as described above. For actual wiring and detailed instructions, please refer to the manuals of the selected CPU and inverter.
