Siemens simatic et200sp Manual page 82

Parameters
12.2 Description of parameters
Diagnostics underflow voltage
Line voltage (measuring range) is monitored for tolerance. A violation of the underflow
triggers a diagnostic interrupt.
Diagnostics low limit voltage
Low limit for voltage is monitored. A violation of the low limit triggers a diagnostic interrupt.
Diagnostics overflow cumulative values
A cumulative overflow in the calculated variables is displayed. The values stop at the high or
low limit. A violation triggers a diagnostic interrupt.
Overcurrent tolerance factor
The tolerance factor secondary overcurrent parameter (10 to 100) indicates the tolerable
value of the secondary current in 0.1 A increments (10 = 1 A to 100 = 10 A). Always take
note of the current class of the current transformer being used (1 A, 5 A).
Overcurrent tolerance time
Monitoring time in which the overcurrent is tolerated. 0 means that the monitoring time has
been disabled.
Low limit for measuring current
The configurable low limit for measuring current refers to the secondary currents and is used
to avoid incorrect calculations in the case of very low currents. Incorrect measurements of
very low currents in particular are a cause of inaccuracies in the current transformer used.
Set the low limit for the current measurement to the required value depending on your
process.
Tip: If you want to find the low limit for the current measurement experimentally, set it to a
lower value. Then, feed in a very precise low current and determine the measurement error
that can no longer be tolerated. Afterwards, set the low limit for the current measurement to
the limit value you have determined.
If current falls below the low limit for the current measurement, the following measured
values and derived variables of the affected phase are reset.
● Effective current value
● Neutral conductor current
● Active power
● Reactive power
● Apparent power
● Phase angle
● Power factor
A moving mean value is formed from the power values and they only become "0" after a
corresponding time. The energy meters for active, reactive and apparent energy of the reset
phase do not measure any longer.
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Analog input module AI Energy Meter 480VAC ST (6ES7134-6PA20-0BD0)
Manual, 12/2015, A5E36061895-AA