ABB 5SHX1960L0004 SCR control unit module
Features • Electrical-to-optical converter for the SPA
bus
• Connects the substation secondary
devices to the fibre-optic SPA bus
• High immunity to electrical and electromag netic interference
• Easy mounting and installation
• Complete range of bus connection mod ules for different applications
• Products of the SPACOM product family
and ABB’s Substation Automation system
Application The SPA bus interconnects the substation
protection relays, annunciator systems and
other devices by means of a fibre-optic loop
based on a glass or plastic fibre cable. The
devices are connected to the bus over bus
connection modules type SPA-ZC_ which
convert the electrical signals of the devices to
optical signals for the bus and, vice versa, the
optical signals of the bus to electrical signals
of the devices. All the standard secondary
devices of a substation are equipped with a
serial interface for receiving and transmitting
information.
The serial ports of the devices are TTL,
RS 485 or RS 232 C signal level interfaces.
Bus connection modules are available for
these interface types.
Design The SPA bus connection modules are used in
both ends of the SPA bus, i.e. on the substa tion level for connection of the bus to the
communication units and on the feeder level
for connection of the bus to the substation
secondary devices.
Bus connection module
SPA-ZC 17
The bus connection module SPA-ZC 17 is
used for connecting substation secondary
devices to the SPA bus. It converts the TTL or
RS 485 level signals of the host device to
fibre optic signals for the bus and vice versa.
The unit comprises one 9-pin D type connec tor for the host device and one pair of optical
transceivers for the SPA bus. The module can
be powered from the host device or from a
separate power source. In the latter case the
bus connection module and the fibre-optic
bus remain operative, should the power sup ply from the host device be interrupted.
The bus connection module SPA-ZC 17 can
be used in both master and slave mode.

Bus connection module
SPA-ZC 20
The bus connection module SPA-ZC 20 is
used for multiplying the number of available
fibre-optic loops in a substation. The module
is provided with 15 transceiver pairs, that is it
can form 15 fibre-optic loops. All of the loops
formed by the module carry the same infor mation. In certain applications, where opera tional reliability is of primary concern it can
be recommended to limit the number of sub station secondary devices connected to one
single loop. In these applications the bus con nection module SPA-ZC 20 is applied.
The SPA-ZC 20 is only used in master mode
and it is powered from the device to which it
is connected. The input interface of the
device is of the RS 485 type