User manual
54 GMC-I Messtechnik GmbH
5.9.2 Master-Slave Parallel Connection
Functions
As opposed to direct parallel connection, master-slave parallel
connection offers significant advantages:
Equally suitable for voltage and current regulation
Output parameters (output voltage, cumulative current limiting,
output on/off) are set entirely by the master device.
All interconnected KONSTANTERs are equally loaded.
Connection
Define one power supply as a master device.
Connect master and slave devices as shown in Figure 5.9.2.
Connect the output leads (refer to chapter 2.1.5).
Balance the individual output current values. Keep connector
cable as short as possible, and use the largest possible
conductor cross-section. Perform balancing with RR
sym
.
Figure 5.9.2 Wiring for Master-Slave Parallel Connection
Settings
Initial power-up:
Short circuit the load.
Switch the master on (mains) and configure settings:
SIG1 out
Pon rcl
OUTPUT off
USET = Uset Desired output voltage
ISET = Isoll / n Iset: Desired cumulative current
n: Number of devices
Only valid if nominal data are
identical for all devices, see notes.
Switch slave 1 on (mains) and configure:
trG out
SIG1 out
Pon rcl
USET > USET
master
The voltage setpoint at the slave devices
must be set at least 1% higher than at the
master device, e.g. to maximum.
ISET = 0 A The ISET rotary knob can be deactivated if
desired by setting ILIM to 0 A.
Use the same procedure for additional slave devices.
Press the OUTPUT ON key at the master. All slave outputs are
switched on simultaneously and configured.
Check output current at the slave device displays.
Output current at each of the slaves can be precisely matched to
master output current by adjusting R
sym
. Changes appear
immediately at the respective display.
Undo short-circuiting of the load.
From this point on, setting and regulation of (cumulative) output
parameters are controlled entirely by the master device.
Power-up after initial settings:
Devices can be switched on and off in any desired order.
Functional Principle
The master controls output current of the downstream device
(slave 1) via the slave’s current control input with the help of the
current monitoring signal.
Slave 1 functions as a master device for the next downstream
slave (slave 2), and so forth.
Cumulative output current is thus always proportional to
master output current.
The master controls the output on / off status of the slave
devices via the connection from the master SIG1 output (SIG1 out
setting) to the Slave TRG input (trG out setting).
Notes:
KONSTANTERs with Differing Nominal Values
The KONSTANTER with the smallest nominal voltage value must
always be used as the master device.
The voltage setting range of the other KONSTANTERs must be
limited to this lowest value with the ULIM parameter.
Slave output current Iout corresponds to master output current
Iout as a percentage only, relative to I
nom
.
Example:
General
A wire connection can be used instead of R
sym
if no precise
setpoint value is required for cumulative output current. In this
case, each slave device supplies slightly more current than the
master device.
If analog interface connector cables and the sensing leads are
longer than 1 meter, shielded cable should be used.
The shield is connected to the ground terminal on the housing or
to OUT.
The master device’s measuring function acquires commonly
generated output voltage for all interconnected KONSTANTERs,
but only acquires its own output current.
The individual measured current values for each of the
interconnected KONSTANTERs must be added together in
order to arrive at cumulative output current.
+ SENSE
OUT
OUT
SENSE
Analog Interface
SIG1 OUT
SIG2 OUT
TRG IN
TRG IN
+15 V
AGND
Uset
Uset +
Iset +
U-MON
I-MON
+ OUT
+ OUT
Master
Settings
USET = Uset
ISET = Iset / n
OUTPUT on/off
+ SENSE
OUT
OUT
SENSE
Analog Interface
SIG1 OUT
SIG2 OUT
TRG IN
TRG IN
+15 V
AGND
Uset
Uset +
Iset +
U-MON
I-MON
+ OUT
+ OUT
Slave 1
Settings
USET > Uset
master
ISET = 0 A
OUTPUT on
+ SENSE
OUT
OUT
SENSE
Analog Interface
SIG1 OUT
SIG2 OUT
TRG IN
TRG IN
+15 V
AGND
Uset
Uset +
Iset +
U-MON
I-MON
+ OUT
+ OUT
Load
= only required for sensing mode operation
1 k
Slave 2
Settings
USET > Uset
master
ISET = 0 A
OUTPUT on
1 k
Output
Output
Output
R
sym
R
sym
trG out
SIG1 out
trG out
SIG1 out
SSP KONSTANTER
SSP KONSTANTER
SSP KONSTANTER
Master: SSP 120-20 U
nom
20 V I
nom
10 A
Settings: USET :12 V ISET : 3 A (30%)
Slave 1: SSP 120-20 U
nom
20 V I
nom
10 A
Results in Uout :12 V Iout : 3 A (30%)
Slave 2: SSP 120-40 U
nom
40 V I
nom
6 A
Results in Uout :12 V Iout : 1.8 A (30%)