Case 1: Local control box for lifting pump in sewage treatment plant (stock renovation)

System architecture: GE 90-30 CPU 351+IC693MDR390, used for local control substation of a single lift pump

8-way DI: manual/automatic transfer switch, local start button, stop button, pump fault feedback, overload relay, liquid level high/low limit, cabinet door safety switch

8-way relay DO: pump contactor coil, fault alarm light, operation indicator light, remote permission relay, valve opening and closing relay, buzzer, backup 2-channel business logic:

Local mode: The panel button starts and stops the pump, collects the fault signal of the thermal relay, and triggers the sound and light alarm due to the fault;

Remote mode: Receive instructions from the PLC master station to start and stop the pump, and transmit the pump operation and fault status back to the upper level; Reason for selection: The relay output can directly drive the AC220V contactor coil without the need for additional intermediate relays. A single module can handle DI+DO simultaneously, and the control box space is compact; Pain points: Wet working conditions, loss of relay contact life, and replacement of project spare parts with IC693MDR390.

Case 2: Workstation Control of Building Materials Brick and Tile Production Line

System architecture: 90-30 PLC, each workstation is equipped with one IC693MDR390 to control the brick billet transfer station

DI: photoelectric in place sensor, limit switch, emergency stop signal, workstation manual button

DO: Transfer cylinder solenoid valve AC220V, workstation indicator light, fault alarm, conveyor belt start stop contactor business process: photoelectric detection of brick billet in place → output solenoid valve to execute pushing; Reset after confirming the limit is in place; Emergency stop signal input cuts off all workstation outputs; Advantages: Relay output compatible with AC220V solenoid valves, no intermediate conversion required, suitable for discrete logic workstations; One module can handle all IO at this workstation, reducing the number of modules.

Case 3: Auxiliary equipment for metallurgical steel plants (on-site control cabinet for dust removal fan)

System architecture: GE90-30 system, on-site IO interface module for dust removal fan

DI: Fan local start stop button, fan operation feedback, overload, filter differential pressure switch, local/remote switching

DO: Fan alarm light, operation indicator light, fault buzzer, air door switch actuator drive relay Application characteristics: Large on-site interference in steel plants, relay isolation output, universal AC/DC load; Only for signal interface, the high-power main circuit is undertaken by the contactor, and the module is only for coil control;

Attention: The current of each channel should be strictly controlled within 2A, and intermediate relays should be added externally for high-power loads.

Case 4: Maintenance and replacement of packaging assembly line equipment for old projects

Old equipment original IC693MDR390 damaged, replaced with refurbished/stock spare parts:

DI: Detecting material photoelectric, safety door, manual operation button;

DO: Conveyor belt start relay, removal cylinder, alarm light;

Scenario: There are not many IO points on the device, and a 16 point mixed IO is just enough for a single workstation. I don’t want to change the original wiring program, so I just plug and replace the same model module directly.

Case 5: Small pump station, water supply and drainage monitoring substation

DI: Float level switch, pump operation feedback, fault signal, manual operation;

DO: Pump start stop relay, high and low liquid level alarm, valve drive;

Features: There are both 24V DC sensor inputs and AC220V alarm lights and contactors on site, and the relay output module is very compatible.