Protronic 100/500/550 and Digitric 500 MODBUS Interface Manual

This manual describes the MODBUS interface for ABB Protronic 100/500/550 and Digitric 500 controllers, covering RS-232 and RS-485 communication, telegram structures, CRC checksums, and MODBUS functions (01, 03, 05, 06, 08, 15, 16). It includes detailed register and coil tables for global variables, data computation methods (REAL, INT, DINT, LONG, exponent-mantissa), and programming examples for reading/writing registers.