General Electric IC670MDL740 Discrete Output Module

The 12/24 VDC Positive Output Module (IC670MDL740) provides a set of 16 discrete outputs. The outputs are positive logic or sourcing outputs. They switch the load to the positive side of the DC power supply, thereby supplying current to the load.

Power Sources

The power to run the module itself comes from the power supply in the bus interface unit.

An external DC power supply must be provided to the switch that powers the load. Inside the module, the external power supply is connected to a 5A fuse. During operation, the module monitors this power supply to ensure that it is above 9.8VDC. If it is not, the bus interface unit interprets this as a fault.

Module Operation

After checking the Board ID and confirming that the module is receiving proper logic power from the Bus Interface Unit (as reflected by the status of the module's power LED), the Bus Interface Unit then sends output data to the module in a serial format. During the transmission, the module automatically loops this data back to the Bus Interface Unit for verification.

A serial-to-parallel converter converts this data into the parallel format required by the module. Opto-isolators isolate the logic components of the module from the field outputs. Power from an external power supply is used to drive a field effect transistor (FET) that provides current to the load.