Method for controlling ABB ACS800 series frequency converters using Modbus bus

I. Hardware Installation and Connection:

• Insert the RMBA card into the SLOT 1 port of the ACS800 and secure it with screws.
• Connect the communication cable to the A, B, and GND interfaces of the RMBA card.

II. Frequency Converter Parameter Settings:

• Modify 98.02 to "Std Modbus".
• Modify 98.07 to "ABB DRIVES".
• Set 52.01 to the station number.
• Configure 52.02 to the baud rate (default is 9600).
• Set 52.03 to the data length and check mode.
• Change 10.01 (External 1 Command) to "COMM" (if needed to control the frequency converter start/stop).
• Modify 11.02 (External Control Selection) to "EXT1" (if needed to control the frequency converter speed).
• Set 11.03 (Setpoint 1 Selection) to "COMM" (if needed to control the frequency converter speed).
• Change 16.01 (operation permission command) to "YES".

III. Modbus addressing of the frequency converter:

• Correspondence between Modbus register areas and frequency converter registers:
  • 40001-40096 correspond to data set registers
  • 40101-49999 are used for parameter registers

40101-49999

40101-49999 are used for parameter registers, where the thousands and hundreds digits correspond to the parameter group number, and the tens and units digits correspond to the parameter number within the group (e.g., 40103 corresponds to parameter 03 of group 01 in the frequency converter). The refresh cycle of parameter register groups is relatively slow.

Note:ACS800supportsModbusspecifies a zero-based addressing space in its technical specifications. The holding registeris 40002, and the address in theIn Modbusmessage is0001. Similarly, the coil40103 in address in theModbus message is0102.

. IV. Reading frequency converter signals:

• Use function code 03 to read frequency converter data.

V. Controlling the start and stop of the frequency converter:

1. Initialization: Write 1142 (hexadecimal value 476) to Modbus register 40001 and delay for at least 100 milliseconds.
2. Stop: Write 1143 (hexadecimal value 477) to Modbus register 40001.
3. Start: Write 1151 (hexadecimal value 47F) to Modbus register 40001.

Example: Communication initialization: Send out [01 06 00 00 04 76 CRC check code], delay for 100 milliseconds; Start motor: Send out [01 06 00 00 04 7F CRC check code]

Stop motor: Send out [01 06 00 00 04 77 CRC check code]

VI. Modifying frequency converter parameters:

1. Method for modifying the given frequency:
   • Write the set frequency value to communication setting 1 (Modbus register 40002).
2. Method for modifying acceleration time:
   • Write the set acceleration time value to Modbus register 42202, with the specific value determined by the resolution and range of the parameter.

Please note: Perform the above operations in the specified order to ensure correct configuration and control of the frequency converter.