VLT ® 2000 Series I Serial data interface (group 5) (continued) Byte 1: Start byte which in this case must be the character Byte 5-8: Control and status words are used to send commands to the frequency converter and send sta- tus from the frequency converter to the master. The control possibilities of the VLT Byte 2, 3: The two-digit address of the frequency converter. This address is also programmed in parameter 500. Sending to address 00 means broadcasting to all units connected to the serial port. None of the units will reply, but they will carry out the command. Byte 9-12: The parameter number is set in these bytes. Byte 13: Used for the sign for the data value in bytes 14-18.
All characters other than "-" are taken as "+". Byte 4: Control parameter telling the VLT frequency converter what to do with the following data values. Byte 14-18: The data value of the parameter stated in bytes 9-12 is set in these bytes. The value must be a whole number. If a decimal point is needed it is stated in byte 19. U (update): Means that the data value (14-18) must be recorded into the frequency converter. Section 1 Section 2 Section 3 Note: Some data values have brackets with a number, e.g. [0]. Use this number instead of the text data value. R (read): Means that the master wants to read the data value of the parameter stated in bytes 9-12. Byte 19:
The position of the decimal point in data values stated in bytes 14-18. The number states the number of characters after the decimal point. Byte 19 can thus be 1, 2, 3, 4 or 5. Example: The number 23.75 is stated as follows: C (control): Means that the frequency converter only reads the four command bytes (5-8) and returns with status. Parameter number and data value will be ignored. I (read index): Means that it reads index and parameter and returns with status. Parameter is stated in bytes 9-12 and in- dex is stated in bytes 13-18. Byte No. 13 14 15 16 17 18 19 ASCII character + 2 3 7 5 0 3 If byte 19 is 9 this indicates an unknown parameter.
Parameters with indexes are read-only parameters. Action will be taken on the control word. Byte 20, 21: Used for summary control. If no control is necessary cancel the function using ? (ASCII: 63) in the two by- tes. Byte 22 : Stop byte stating the end of the telegram. The character > is used (ASCII: 62) MG.20.B6.02 – VLT is a registered Danfoss trademark 55