Other Applications; Series Connection; Parallel Operation In Master-Slave (Ms) - Elektro-Automatik ELR 9000 Betriebsanleitung

3.10

Other applications

3.10.1

Series connection

Series connection is not a permissible operating method for electronic loads and must not be
installed or operated under any circumstances!
3.10.2

Parallel operation in master-slave (MS)

Multiple devices of same kind and model can be connected in parallel in order to create a system with higher total
current and hence higher power. For true master-slave operation, the units have to be connected with their DC
inputs, their master-slave bus and their Share 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 will dynmically balance the units in their internal current regulation, especially if the master unit
runs a function like sine wave etc. 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.
3.10.2.1 Restrictions
Compared to normal operation of a single device, master-slave operation has some limitations:
• The MS system reacts differently to alarm situations than a single unit (see below in 3.10.2.6)
• Using the Share bus makes the system reacts as dynamically as possible, but it is still not as dynamic as single
unit operation
• A device which was configured as slave has limited operability (only access to MENU possible)
3.10.2.2 Wiring the DC inputs
The DC input of every unit in the parallel operation is simply connected to the next unit using cables with cross
section according to the maximum current and with short as possible length.
3.10.2.3 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 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
inputs of the devices
A max. of 10 units can be connected via Share bus.
3.10.2.4 Wiring and set-up of the master-slave bus
The master-slave connectors are built-in and must first be connected via network cables (≥CAT3, patch cable) and
then MS can be configured manually (recommended) or by remote control. The following applies:
• Type of connection: RS485 with 500000 baud
• A maximum 10 units can be connected via the bus: 1 master and up to 9 slaves.
• Only devices of same kind, i.e. electronic load to electronic load, and of the same model, such as ELR 9080-170
to ELR 9080-170.
• Units at the end of the bus must be terminated (see below)
The master-slave bus (RS485) must not be wired using crossover cables!
Later operation of the MS system implies:
• the master unit displays, or makes available to be read by the remote controller, the sum of the actual values
of all the units
• the range for setting the values of the master is adapted to the total number of units, thus, if e.g. 5 units each with
a power of 7 kW are connected together to a 35 kW system, then the master can be set in the range 0...35 kW
EA Elektro-Automatik GmbH
Helmholtzstr. 31-33 • 41747 Viersen
Germany
Fon: +49 2162 / 3785-0
Fax: +49 2162 / 16230
ELR 9000 Series
www.elektroautomatik.de
ea1974@elektroautomatik.de
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