Reference: A938
Index: B
Page 53
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Instruction Manual – NPS914 Alarm and Indication IED
6. Object control and monitoring
The object control and monitoring function takes care of both for circuit breakers and disconnectors. The
monitoring and controlling are based on the statuses of the relay's configured digital inputs and outputs.
The number of controllable and monitored objects in each relay depends on the device type and amount
of digital inputs. One controllable object requires a minimum of two (2) output contacts. The status
monitoring of one monitored object usually requires two (2) digital inputs. Alternatively, object status
monitoring can be performed with a single digital input: the input's active state and its zero state (switched
to 1 with a NOT gate in the Logic editor).
An object can be controlled manually or automatically. Manual control can be done by local control, or by
remote control. Local manual control can be done by relays front panel (HMI) or by external push buttons
connected to relays digital inputs. Manual remote control can be done through one of the various
communication protocols available (Modbus, IEC101/103/104 etc.). The function supports the modes
"Direct control" and "Select before execute" while controlled remotely. Automatic controlling can be done
with functions like auto-reclosing function (ANSI 79).
Object control consists of the following:
• control logic
• control monitor
• output handler.
In addition to these main parts, the user can add object-related circuit breaker failure protection (CBFP;
50BF) and object wear monitoring in the object control block. These additional functions are not included
in the basic version of the object control block.
The main outputs of the function are the OBJECT OPEN and OBJECT CLOSE control signals.
Additionally, the function reports the monitored object's status and applied operations. The setting
parameters are static inputs for the function, which can only be changed by the user in the function's setup
phase.
The inputs for the function are the following:
• digital input status indications (the OPEN and CLOSE status signals)
• blockings (if applicable)
• the OBJECT READY and SYNCHROCHECK monitor signals (if applicable).
• Withdrawable cart IN and OUT status signals (if applicable).
The function generates general time stamped ON/OFF events to the common event buffer from each of
the two (2) output signals as well as several operational event signals. The time stamp resolution is 1 ms.
The function also provides a resettable cumulative counter for OPEN, CLOSE, OPEN FAILED, and
CLOSE FAILED events.