5
The same flat cable further contains a monitor-
ing bus for internal faults and an interlocking
bus for the transmission of interlocking signals
between the annunciator modules. When seve-
ral annunciator units SACO 64D4 are built
together, the SPA-bus can be used for synchro-
nizing the flashing sequence of the alarm indi-
cators of the modules.
In a distributed system bus connection mod-
ules type SPA-ZC_ are used for connecting the
annunciator unit to the SPA-bus. Bus connec-
tion modules are available for both optical and
electrical data transmission. The transmission
distances vary with the transmission media, the
following values can be given:
- plastic-fibre: at least 30 m
- glass-fibre: at least 1 km
- pairs of twisted conductor without galvanic
isolation: at least 30 m
- pairs of twisted conductor with galvanic iso-
lation: at least 200 m
Fiber optic media is always recommended due
to its good resistance to electromagnetical in-
terference.
The setting values, groupings and interlockings
of the annunciator modules are stored in non-
volatile memories.
In a stand-alone annunciator system without a
higher level system connected the modules can
be programmed by temporarily connecting the
programming module SACO 16PM to the an-
nunciator modules SACO 16D2B.
If SACO 64D4 is connected to a higher level
system, e.g MicroSCADA the programming
might be made from there. A SMS software can
also be used for programming the SACO 64D4.