Siemens SIMATIC ET 200SP Manual page 59

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 value [0.1 A]
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 ms 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
● 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.
Current transformer primary current
Enter here the nominal value for the primary current of the current transformer used. The
transformer ratio is calculated from the primary and secondary current.
Analog input module AI Energy Meter 400VAC ST (6ES7134-6PA01-0BD0)
Manual, 10/2017, A5E36061895-AB
Parameters
8.2 Description of parameters
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