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CET Electric Technology
Universal Hysteresis
The hysteresis rate for calculating the Return Threshold for all Alarms, except for
Dip/Swell and Interruption Alarms.
0 to 10%, 2%*
Current ON Threshold
The ON Threshold that applies to all Mains and Branch Current Inputs for
switching from the OFF to ON state.
0 to 10%, 5%*
Current ON Delay
The minimum duration that the Current of a particular Current Input must
exceed the Current ON Threshold before the Status would switch from OFF to
ON.
0 to 9999(s)
10s*
Current OFF Delay
The minimum duration that the Current of a particular Current Input must fall
below the Current OFF Threshold before the Status would switch from ON to
OFF.
0 to 9999(s)
30s*
Table 4-10 Global Parameters
The Universal Hysteresis is a global parameter that is used to prevent an alarm from fluctuating between
the Active and Inactive states around the threshold point.
It should be noted that the
Current ON Limit
is calculated based on the Breaker Rating parameters.
Therefore, it’s critical to set the Breaker Rating correctly for each Current channel for the Current
Alarms to work properly.
Current ON Limit = Channel’s Breaker Rating x Current On Threshold (%)
Current OFF Limit = Current ON Limit x (1 - Universal Hysteresis)
The PMC-592 provides an internal Current ON/OFF status for each Current channel to indicate whether
the channel is ON (Loaded) or OFF (No Load). If the channel status is OFF and has never been ON, it
means that the channel has no load and would prevent the Low and Low-Low alarms from activating.
In Firmware V1.00.10 or later, the
Current OFF Alarm Enable
parameter (Modbus Register 6394) has
been added to ensure that the Current L/LL Alarms would remain Active even when the Current
transitions from the ON to OFF state if
Current OFF Alarm Enable
is enabled. The Current L/LL Alarms
would be reset only if the Current returns to the ON state. For Firmware V1.00.09 or earlier, the Current
L/LL Alarms would be reset immediately when the Current transitions from the ON to OFF state, similar
to having the
Current OFF Alarm Enable
parameter disabled.
The following figures illustrate the logic diagram of the Current ON/OFF status, respectively.
Figure 4-6 Current ON Logic Diagram
Figure 4-7 Current OFF Logic Diagram