© EA Elektro-Automatik in 2022, this information is subject to change without notice
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06230820_manual_psi_10000_3u_15kw_en_01
3.11.1.4 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 64 units can be connected via the bus: 1 master and up to 63 slaves.
•
Connection only between devices of same kind, i.e. power supply to power supply; connection of different power classes
is allowed and supported, e. g. one 15 kW 3U with one 30 kW 4U to achieve a total of 45 kW, but requires to have at least
firmware KE/HMI 3.02 installed on all units
•
Linking different series is supported, but limited to:
•
PS 10000 series models can be used as slave units for PSI 10000 series models being the master unit
•
Units at the end of the bus should be terminated, if necessary (see below for more information)
The master-slave bus 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 ranges for setting the values, adjustment limits, protections (OVP etc.) and user events (UVD etc.) of the master are
adapted to the total number of units. Thus, if e.g. 5 units each with a power of 15 kW are connected together to a 75 kW
system, then the master can be set in the range 0...75 kW.
•
Slaves are no operable as long as being controlled by the master
•
Slaves which haven’t yet been initialized by the master will show the alarm
MSP
in the display. The same alarm is signaled
upon MS bus errors.
►
How to connect the digital master-slave bus
1.
Switch off all units and connect the master-slave bus with network cables (CAT3 or better, cables not included). It
doesn’t matter which of the two master-slave sockets (RJ45, backside) is connected to the next unit.
2.
Depending on the desired configuration the units are then also connected at their DC terminals.
The two units at the beginning and end of the chain must be terminated, while the master
requires a separate setting. See table below.
Termination is done with internal electronic switches which are controlled from within the
Settings
menu of the device in group
Master-slave
. This can be done as part of setting up
every unit as master or slave, but should be done before the master is going to be set as
Master
, because doing so immediately triggers a bus initialization. In group
Master-Slave
the termination resistors for BIAS and the bus itself (TERM, see figure to the right) can be
set separately. Settings matrix for the units on the MS bus:
Device position
Termination setting(s)
Master (at end)
BIAS + TERM
Master (central)
BIAS
Slave (at end)
TERM
Slave (central)
-
R
R
+
B
A
BIAS
BIAS
MS
Bus
R
TERM
3.11.1.5 Mixed systems
As mixed systems following is understood:
•
Different power classes, like 5 kW, 15 kW or 30 kW within one master-slave system (requires at firmware KE 3.02)
•
Different series, specifically PSI 10000 series in connection with PS 10000 series (requires at firmware KE 3.02)
Both mixed systems are supported, but also their combination. The use of a “PS” series device as slave for a “PSI” series
master wasn’t possible before, because the PS has no resistance mode, contrary to the PSI. Today, this is circumvented by
temporarily enabling resistance control for a PS in slave operation. Vice versa, a PS cannot be the master of a PSI.
When connecting devices with different feature sets it makes sense to select the one with the best configuration as master.
Combining different power classes can have an unexpected side effect, such that the resulting total power, as displayed by
the master after the initialization, isn’t the expected one, but lower. This depends on what unit and power class has been
picked as master. In such a situation the golden rule is: always select the master from the units with the highest power rating.
