Digital inputs related to two-bit DPC or DPS objects, for instance circuit breaker and disconnectors, have a multiple mapping in the Modbus address space. The objects’ open and close bits are coded as MOM+MCD bit pair entities. The MCD bit reveals if the object has changed its position several times since the Modbus client last scanned it. The open and close bits are also coded using MOM values only, together with a fault bit. The fault bit is set to "1" when the object is in intermediate (00) or faulty (11) position.
| Bits | Treatment |
|---|---|
| Close MOM | One 2 bit entity |
| Close MCD | |
| Open MOM | One 2 bit entity |
| Open MCD | |
| : | |
| Close MOM | One 1 bit entity |
| Open MOM | One 1 bit entity |
| Faulty position MOM | One 1 bit entity |
| : |
The MOM values are identical in each entity. The MCD bit is only reset if the MOM bit in the same entity is read.