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83
-
507
-
013 Rev. D
41
5.15 PARALLEL OPERATION
Up to four units of the same VOLTAGE and CURRENT rating can be connected in parallel to provide
up to four times the Output Current ca
pability. One of the units operates as a Master and the remai
n-
ing units are Slaves. The Slave units are analog programmed by the Master unit. In remote digital o
p-
eration, only the Master unit can be programmed by the computer, while the Slave units may be
co
n-
nected to the computer for voltage, current and status readback only. Follow the following procedure
to configure multiple supplies for parallel operation. Refer to Sec. 5.15
.1
and to Sec. 5.15.2 for d
e-
tailed explanation.
5.15.1
Basic parallel operation
In thi
s method, setting the units as Master and Slaves is made by the rear panel J1 connections and
the setup switch SW1. Each unit displays its own output current and voltage. To program the load cu
r-
rent, the Master unit should be programmed to the total load c
urrent divided by the number of units in
the system. Refer to the following procedure to configure multiple supplies for basic parallel operation.
1. Setting up the Master unit
Set the Master unit Output Voltage to the desired voltage. Program the Output C
urrent to the desired
load current divided by the number of parallel units. During operation, the Master unit operates in CV
mode, regulating the load voltage at the programmed Output Voltage. Connect the sensing circuit to
l
o
cal or remote sensing as shown
in Fig.5
-
4 or fig.5
-
5.
2. Setting up the Slave units
-
1.
The Output Voltage of the Slave units should be programmed 2
-
5% higher than the Output
Voltage of the Master unit to prevent interference with the Master unit’s control. The Output
Current settin
g of each unit should be programmed to the desired load current divided by the
number of pa
r
allel units.
-
2. Set the rear panel setup switch SW1 position 2 to the up position.
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3. Connect a wire jumper between J1
-
8 and J1
-
12 (refer to Table 4
-
4).
-
4. Conne
ct J1 terminal 10(IPGM) of the slave unit to J1 terminal 25(P) of the master unit.
During operation, the Slave units operate as a controlled current source following the Master Ou
t-
put Current. It is recommended that the power system be designed so that eac
h unit supplies up
to 95% of its current rating because of the imbalance which may be caused by cabling and co
n-
nection vol
t
age drop.
3.
Daisy Chain Connection: (See Fig. 5
-
6)
These set up
and
connections
are optional but is strongly recomm
ended. It
w
ill shut
down all power
su
p
plies
when a
fault condition occurs in any one of them.
o
Switch SW1 position 5 should be in its down position for all power supplies.
o
Connect J1
-
16 of the Master Supply to J1
-
15 of the ‘First’ Slave Supply (If any).
o
Connect J1
-
16 of the ‘F
irst’ Slave Supply to J1
-
15 of the ‘Second’ Slave Supply (if any).
o
Connect J1
-
16 of the ‘Second’ Slave Supply to J1
-
15 of the ‘Third’ Slave Supply (If any).
o
Connect J1
-
16 of the ‘Last’ Slave Supply to J1
-
15 of the ‘Third’ Slave Supply (If any).
o
Connect J1
-
2 (or J1
-
3) common to all supplies (See Fig. 5.6).
4.
Setting Over Voltage protection
The Master unit OVP setting should be programmed to the desired OVP level. The OVP setting of
the slave units should be programmed to a higher value than the Master OVP. Whe
n the Master
unit shuts down, it programs the Slave unit to zero Output Voltage. If a Slave unit shuts down
(when its OVP is set lower than the Master Output Voltage), only that Slave unit would shut down,
and the remai
n
ing Slave units would supply all of
the load current.
5.
Setting Foldback protection
Foldback protection, is desired, may only be used with the Master unit. When the Master unit
shuts down, it programs the Slave units to zero Output Vol
t
age.