Local Operation 
 
3-50  M370430-01  Rev B 
Configuring Multiple Supplies for Current Sharing Operation 
(APG Method) 
Up to four power supplies can be connected in parallel to increase the 
output current. One of the units will operate as the master unit and the 
remaining units will operate as slave units controlled by the master unit. 
The master unit uses the analog programming lines to set the output 
voltages and currents of the slave units to match its output. 
In remote digital operation, only the master unit can be programmed 
remotely while the slave units that are connected remotely will only 
provide voltage, current and status readback information. 
In  APG  current  sharing  topologies,  only  the  master  unit  can  be 
programmed using any of the input methods (front panel, remote digital, 
or analog programming control). The slave unit(s) voltage and current 
output(s) are determined by the master unit through the REF_I input to 
each slave  unit.  The  readback  using  any of the  monitoring  methods 
(front panel display, user monitor lines or SCPI measure commands) of 
each  unit  (master  or  slave)  will  provide  individual  unit  status,  not 
system status. 
Important: If current sharing is not being used, the unit must be configured as 
a controller. Failure to do so will result in unpredictable operation. 
 
Setting up the Controller Unit 
Set the output voltage of the master unit to the desired voltage. Program 
the current set point of the master unit to the desired load current set 
point divided by the number of parallel units. During operation, the 
master unit operates in Constant Voltage mode, regulating the load 
voltage at the programmed output voltage. Send the Current share SCPI 
command or use the following instructions to program front panel 
current share setup: 
1.  With the 9-position mode control at the PGM position, press 
the rotary Adjust/Enter control. 
 is displayed on the output voltage display. 
2.  Turn the rotary Adjust/Enter control to select   and 
press the Adjust/Enter control. 
 is displayed on the output voltage display. 
3.  Turn the rotary Adjust/Enter control to select   in the 
output current display.