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1MRS755225
Transformer Terminal
Technical Reference Manual, General
RET 54_
Normally the time-out parameter of the client must always be adjusted in accordance
with the IED command time-out parameter (longer time-out on the client side). At
all times there shall be only one communication port from which secured object
control is possible.
The command time-out parameter is located in MAIN MENU/Communication/
General.
For more information about secured object control refer to the control function block
manuals.
Setting the command time-out parameter for LON
communication
The correct command time-out parameter value depends on how many LON
communication inputs are in use (COMM_INx variables). If no horizontal
communication is used, 1.5 seconds shall be used as time-out.
In order to take full advantage of the secured command handling procedure, the
complete scenario must be known.
There are two scenarios:
1. Confirmed command handling with NV poll support: NV poll selected by the
LNT tool.
2. Command handling with asynchronous blockings.
Confirmed command handling with NV poll support
If LON NV polling is used for communication inputs, the time-out must be based on
the minimum time-out, and is calculated from:
amount_of_polled_inputs*poll_timeout*(retries+1)
which gives a typical minimum value of:
amount_of_polled_inputs*128ms...256ms*5
(see the LN settings and refer to the instructions given for default time-outs).
An over dimensioned longer time-out will not cause any harm, because the operation
will always be faster in real life than the maximum time-out.
On application side, the comm_in and comm_outs need to be used systematically to
ensure that exceptions to the normal operation are handled correctly (e.g. handling
of the live bits).
Command handling with asynchronous blockings
Figure 4.1.13.8-1 shows the asynchronous blocking principle of sending the reserve-
output state to the block-inputs of other bays. As horizontal communication is
trusted directly, 1.5 seconds shall be used as command time-out.
For more information about asynchronous blockings refer to the horizontal
communication engineering tip in the Protection & Control Terminals REF 54_,
RET 54_, REM 54_, REC 523 Configuration Guideline .
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