Для контроля состояния по Modbus необходимо читать слово IOL W4066 (10#4066):
Bit 0: Logic input LI3 (0 – low state / 1 – high state).
Bit 1: Logic output LO1 (0 – low state / 1 – high state).
Bit 2: Logic output LO2 (0 – low state / 1 – high state).
Bit 3: Relay R1 (0 – open / 1 – closed).
Bit 4: Relay R2 (0 – open / 1 – closed).
Bit 5: Reserved.
Bit 6: Logic input LI_RUN (0 – low state / 1 – high state).
Bit 7: Logic input LI_STOP (0 – low state / 1 – high state).
Bit 8: Reserved.
Bit 9: Logic input LI4 (0 – low state / 1 – high state).
Bit 10: Relay R3 (0 – open / 1 – closed).
Bits 11 to 15: Reserved.
Bit 0: Logic input LI3 (0 – low state / 1 – high state).
Bit 1: Logic output LO1 (0 – low state / 1 – high state).
Bit 2: Logic output LO2 (0 – low state / 1 – high state).
Bit 3: Relay R1 (0 – open / 1 – closed).
Bit 4: Relay R2 (0 – open / 1 – closed).
Bit 5: Reserved.
Bit 6: Logic input LI_RUN (0 – low state / 1 – high state).
Bit 7: Logic input LI_STOP (0 – low state / 1 – high state).
Bit 8: Reserved.
Bit 9: Logic input LI4 (0 – low state / 1 – high state).
Bit 10: Relay R3 (0 – open / 1 – closed).
Bits 11 to 15: Reserved.