Inputs for the function are the operating mode selections, setting parameters and measured and pre-
processed current magnitudes and binary input signals. Function outputs START, TRIP and BLOCKED
signals which can be used for direct IO controlling and also for user logic programming. The function
registers its operation into 12 last time-stamped registers and also generates general time stamped
ON/OFF events to the common event buffer from each of the three output signal. In instant operating
mode the function outputs START and TRIP events simultaneously with equivalent time stamp. Time
stamp resolution is 1ms. Function provides also cumulative counters for START, TRIP and BLOCKED
events.
In the following gure is presented the simpli ed function block diagram of the NOC function.
Figure. 5.4.1. - 17. Simpli ed function block diagram of the NOC function.
Measured input values
Function block uses analog current measurement values. Function block always utilizes peak-to-peak
measurement from samples and by user selection the monitored magnitude can be either fundamental
frequency RMS values, True RMS values from the whole harmonic specter of 32 components or peak
to peak values. -20ms averaged value of the selected magnitude is used for pre-fault data registering.
Table. 5.4.1. - 49. Analogic magnitudes used by the NOC function.
Signal
Description
Time base
IL1PP
Peak-to-peak measurement of phase L1/A current
5 ms
IL2PP
Peak-to-peak measurement of phase L2/B current
5 ms
IL3PP
Peak-to-peak measurement of phase L3/C current
5 ms
IL1RMS
Fundamental RMS measurement of phase L1/A current
5 ms
IL2RMS
Fundamental RMS measurement of phase L2/B current
5 ms
IL3RMS
Fundamental RMS measurement of phase L3/C current
5 ms
IL1TRMS
TRMS measurement of phase L1/A current
5 ms
IL2TRMS
TRMS measurement of phase L2/B current
5 ms
IL3TRMS
TRMS measurement of phase L3/C current
5 ms
Selection of the used AI channel is made with a setting parameter. In all possible input channel
variations pre-fault condition is presented with 20 ms averaged history value from -20 ms of Start or
Trip event.
AQ-T257
Instruction manual
Version: 2.00
43
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