ABB RER670 Applications Manual page 463

1MRK 506 375-UEN A
Railway application RER670 2.2 IEC
Application manual
Using Echo in this case is safe only if there is no risk of varying
transmission asymmetry.
GPSSyncErr: when GPS synchronization is lost, synchronization of the line
differential function continues for 16 s based on the stability in the local IED
clocks. After that, setting Block blocks the line differential function or setting Echo
keeps it on by using the Echo synchronization method.
Using Echo in this case is safe only if there is no risk of varying
transmission asymmetry.
CommSync defines the Master and Slave relation in the communication system,
and should not be mistaken for the synchronization of line differential current
samples. When direct fibre is used, one LDCM is set as Master and the other as
Slave. When a modem and multiplexer is used, the IED is always set as Slave
because the telecommunication system provides the clock master.
OptoPower has two settings: LowPower is used for fibres 0 – 1 km and HighPower
for fibres >1 km.
ComAlarmDel defines the time delay for communication failure alarm. In
communication systems, route switching can sometimes cause interruptions with a
duration of up to 50 ms. Too short a time delay can thus cause nuisance alarms.
ComAlrmResDel defines the time delay for communication failure alarm reset.
RedChSwTime defines the time delay before switching over to a redundant channel
in case of primary channel failure.
RedChRturnTime defines the time delay before switching back to the primary
channel after channel failure.
AsymDelay denotes asymmetry which is defined as transmission delay minus
receive delay. If fixed asymmetry is known, Echo synchronization method can be
used, provided that AsymDelay is properly set. From the definition follows that
asymmetry is always positive at one end and negative at the other end.
MaxTransmDelay indicates maximum transmission delay. Data for maximum 40
ms transmission delay can be buffered up. Delay times in the range of some ms are
common. If data arrive in wrong order, the oldest data is disregarded.
MaxtDiffLevel indicates the maximum time difference allowed between internal
clocks in respective line ends.
64 kbit mode specific settings
TransmCurr is used to select among the following:
Section 19
Remote communication
457