Safety
Modbus devices may control physical equipment.
Write operations must be used carefully.
Before writing a coil or holding register, verify:
Target IP address
TCP port
Device ID
Register or coil address
Whether the address is writable
Permitted value range
Physical effect of the write
Do not experiment with unknown writable addresses on production systems.
Read Operations
Read operations are safer than writes but can still affect constrained industrial devices if excessive scanning generates unnecessary traffic.
Use appropriate ranges and timeouts when scanning production systems.