A freeze operation can be issued either by a master command C_CI_NA_1 (QCC=FRZ), or by an internal freeze pulse applied to the I5CLPRT function block’s input IT_FRZ.
The new frozen counter values can be either sent spontaneously to the master, or they can remain internally in the protocol stack for later reading by the master using command C_CI_NA_1 (QCC=RQT).
A new freeze operation overwrites the previously stored frozen counter values.
The freeze command operation C_CI_NA_1 (QCC=FRZ) can be defined to be “freeze only” or “freeze and reset”. In the latter case, the protocol tries to reset the counters after the value freezing. Some IEC 61850 counters cannot be physically reset. The counters in this device are globally reset for all possible readers, for example, for other protocols and for reading via HMI.
Two setting parameters define how the freeze operation is handled.
- Freeze mode defines if the I5CLPRT function block's IT_FRZ input is used, and if the externally triggered operation is “freeze only” or “freeze and reset”.
- Counter reporting defines what happens after the counters have been frozen. Frozen counters can be configured for spontaneous reporting with this setting.