Siemens SICLOCK TC 400 - Manual (Page 83)

Parameterization
9-81 © Siemens AG 2007 All Rights Reserved
SICLOCK
® TC 400
9.2.4 OUTPUT 1 and 2 redundant
A redundant point-to-point connection can be implemented with two SICLOCK TC
400 devices. Both devices must be synchronous. Typically, this is ensured by
device 2 using device 1 as external synchronization (e.g. device 2 as NTP client
and device 1 as NTP server).
See also Redundancy (Section 2.6) and Redundant point-to-point connec-
tions (Section 6.4.2).
The output for OUTPUT 1 or 2 of device 1 is set to "only if synchronized", the out-
put for OUTPUT 1 or 2 of device 2 to "send unconditional".
Example:
OUTPUT 1 of both devices is to be operated redundantly.
Device 1:
Parameter entry /Outputs/Output 1/conditional output (0.12.01) = "only if synchro-
nized"
Device 2:
Parameter entry /Outputs/Output 1/conditional output (0.12.01) = "send uncondi-
tional"
Table 9-1 Redundancy response in various situations
Synchronization Response
Device 1 Device 2
External synchronization Radio
clock
Device 1 The time receiver receives the signal from both
devices. The lack of definition is in the µs range and
can be ignored.
External synchronization None Radio
clock
The time receiver receives the signal from device 2.
(Because of the setting "Only if synchronized", device 1
does not supply the time in this case.)
External synchronization None None The time receiver receives the signal from device 2.
(Because of the setting "Only if synchronized", device 1
does not supply the time in this case.)
External synchronization Radio
clock
Radio
clock
If the device 1 – device 2 connection is faulted, the time
receiver receives the signal from both devices. There is
a lack of definition in the accuracy of the external syn-
chronization which is usually in the µs range and can
be ignored.
Large inaccuracies can occur when an external syn-
chronization also supplies a faulty signal.