ABB Rellon 620 Series, Руководство по протоколу связи

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Section 2
1MAC306892-MB C
IEC 60870-5 overview
12 RER620
Communication Protocol Manual
function checks the permissibility and the validity of the received command message, and
operates if the check results are positive.
The two-step command Select and execute is used by the controlling station to:
• Prepare a specified control operation in a controlled outstation
• Check that the correct control operation is prepared
• Execute the command
The preparation is checked by an operator or by an application procedure. The controlled
outstation does not start the control operation until it has received the correct execute
indication. The command transmission is confirmed to the controlled outstation by an
activation confirmation response. After the command is executed, an activation
termination response is sent to the controlling station.
2.3.6 Changes in protocol and link parameters
When the values of the protocol and link parameters are changed, the new values take
effect after they have been committed.
2.3.7 Acquisition of transmission delay
The value of time correction is determined by the sum of the transmission delay and the
internal equipment delay. The transmission delay is a value which can be acquired either
separately by parameterization, or via a dynamic procedure initiated by the controlling
station.
2.3.8 Analog Value Deadband
In certain situations, the user might want to reduce the number of unnecessary events by
using the deadband feature. This feature is available for analog measurements for each
point and may be configured in the configuration tool by setting the Range and Interval
parameters.
The range can, for example, be 0.05 (5%). If the data point value changes beyond the set
value of 0.05 (5%) from the previously sent value, the data will be sent spontaneously as
deadband data. The interval, however, limits the deadbanded value to be sent once per
configured time window which
is defined of the order of seconds. The interval can be set to zero to disable the time
window limiting feature.