Modicon Controllers
The Modbus RTU Communications option supports reads from the following memory types on Modicon controllers:
Coils | 0xxxx or 0xxxxx |
Inputs | 1xxxx or 1xxxxx |
Input Registers | 3xxxx or 3xxxxx |
Holding Registers | 4xxxx or 4xxxxx |
General Reference | 6yxxxx or 6yxxxxx |
Holding Registers as Double Precision | D4xxxx or D4xxxxx |
The Modbus RTU Communications option supports writes to the following memory types on Modicon controllers:
Coils | 0xxxx or 0xxxxx |
Holding Registers | 4xxxx or 4xxxxx |
General Reference | 6yxxxx or 6yxxxxx |
Holding Registers as Double Precision | D4xxxx or D4xxxxx |
On Modicon controllers, coils that are not programmed in the controller logic program are not automatically cleared on power up. This means that if a coil is set to 1, the output will remain HOT until explicitly set to 0.
Writing to Holding Registers overrides the controller memory protect.