dear sir

i have modbus register . but it have bit 00-15 .Which driver should I use?

If the device you wish to communicate with uses standard Modbus register mapping, you can use the "Modbus Compatible Device" driver along with the appropriate port type (serial, TCP, etc.) and protocol (Modbus RTU, ASCII, TCP).

To extract individual bit values from a register, 40043 for example, you need to set the address field in your Input tags (typically Digital Status for this use) to indicate the register number followed by the bit number with a "/" character separating them. For example:

40043/0 will read bit 0
40043/1 will read bit 1
...
40043/15 will read bit 15

You can learn more about the possible address suffixes here: https://www.trihedral.com/help/Content/D_Tags/Dev_DataSuffixesForTagIO.htm

Hi....i will recommend to test utilizing a RS232 to RS485 converter, and ModScan or something comparable on your PC. Guarantee that you can peruse the proper registers from the Power Meter utilizing the baud rate, equality and so forth that you anticipate.
Testing utilizing the equivalent RS232 to RS485 converter and ModSim or something comparative on your PC. Guarantee that you can peruse the suitable registers from your Computer (into the Arduino) utilizing the baud rate, equality and so forth that you have arranged on your Computer to coordinate what the Power Meter was tried in 1) utilizing.