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EA Elektro-Automatik GmbH
Helmholtzstr. 31-37 • 41747 Viersen
Germany
Fon: +49 2162 / 3785-0
Fax: +49 2162 / 16230
www.elektroautomatik.de
ea1974@elektroautomatik.de
PSI 9000 WR 3U Slave Series
3.7
Other applications
3.7.1 Parallel operation in master-slave (MS)
Running the Slave models of series PSI 9000 WR 3U Slave in master-slave operation is the primary function.
The devices will work as slave units which are enumerated and controlled by a master device. Instructions for
configuration and use of a master-slave system where a standard model with display from series PSI 9000 WR
3U is master can be found in the user manual of PSI 9000 WR 3U series.
This section is about a different situation where a Slave model is supposed to be the master unit as substitute
of a missing or not matching master model. Running the Slave as master is basically possible, though all setup
and control is only done via the USB ports and by software. Since the front USB port is restricted in its functions
and does not support master-slave configuration, we recommend to use the rear USB port for all communication.
3.7.1.1 Introduction
Multiple devices with identical ratings can be connected in parallel in order to create a system with higher total cur-
rent and hence higher power. This can be done using the standard models with display or the new slave models
(PSI 9000 WR 3U Slave, available since mid of 2017). Only disadvantage: the slave models are only available as
15 kW versions, so they only match the 15 kW standard models.
For parallel operation in master-slave mode the units are usually connected with their DC outputs, their Share bus
and their master-slave bus. The master-slave bus is a digital bus which makes the system work as one big unit
regarding adjusted values, actual values and status.
The Share bus is intended to balance the units dynamically in their power, especially if the master unit runs a func-
tion. In order for this bus to work correctly, at least the DC minus poles of all units have to be connected, because
DC minus is the reference for the Share bus.
3.7.1.2 Restrictions
Compared to normal operation of a single device, master-slave operation has some
restrictions
:
•
The MS system reacts differently in alarm situations (see below in
•
Using the Share bus makes the system react as dynamic as possible, but it is still not as dynamic as single unit
operation
3.7.1.3 Wiring the DC outputs
The DC output of every unit in the parallel operation is connected with correct polarity to the next unit, using cables
with cross section according to the maximum current and with as short as possible length.
3.7.1.4 Wiring the Share bus
The Share bus is wired from unit to unit with an ideally twisted pair of cables with non-critical cross section. We
recommend to use 0.5 mm² to 1.0 mm².
• The Share bus is poled. Take care for correct polarity of the wiring!
• In order for the Share bus to work correctly it requires at least to connect all DC minus
outputs of the devices
A max. of 16 units can be connected via Share bus.
3.7.1.5 Wiring and set-up of the digital master-slave bus
The master-slave connectors are built-in and can be connected via network cables (≥CAT3, patch cable). After
this, MS can be configured manually (recommended) or by remote control. The following applies:
•
A maximum of 16 units can be connected via the bus: 1 master and up to 15 slaves.
•
Only devices of same rating, i.e. power supply to power supply, and of the same model, such as PSI 9080-510
WR 3U to PSI 9080-510 WR 3U Slave or also PSI 9080-510 WR 3U Slave with PSI 9080-510 WR 3U Slave.
•
Units at the end of the bus must be terminated (see below)
The master-slave bus must not be wired using crossover cables!
