User Manual    AMETEK Programmable Power 
RS Series    154 
6.5  Non-Routine Calibration 
The non-routine calibration may involve removing the front or top cover of the power source.  
Use extreme caution when performing any of these tasks while the system is connected to AC 
mains and/or powered up. 
6.5.1  Power Source Gain Adjustment 
For any RS configuration that requires two or more amplifiers to be operated in parallel for 
increased current output, the amplifier gains have to matched as closely as possible to ensure 
equal current sharing.  If an unbalance exists between amplifier outputs, one or the other 
amplifier will deliver more current and may run into its current limit protection before full output 
power can be attained. 
This procedure details the gain adjustment.  Generally, RS units are shipped with the gains 
already set correctly so this task should only be undertaken if an amplifier has been replaced or 
if two RS units are to be combined that were not originally shipped from the factory as such. 
To make this adjustment the front cover must first be removed in order to get access to the 
power module output terminals.   
If the power system to be adjusted is an RS180 through RS540, the procedure involves 
matching the output voltage of the A, B and C power modules in the master cabinet to the A, B 
and C power modules in the auxiliary cabinet(s). Proceed as follows: 
1.  Shut off all power to the cabinets. Disconnect the two wires going to Terminal 6 and 
Terminal 7 on the lower front of the power modules. Do this to module A, A’, B, B’, C and C’ 
in the auxiliary cabinet(s) only. Place some temporary insulation over the lug ends. 
2.  Connect a DMM between terminals 6 and 7 on the A module in the master cabinet.  Power 
up the cabinet. Set the controller to the 300V range, program 230V at 60Hz. Enable the 
output by pressing the OUTPUT ON/OFF key. Measure the A module output voltage and 
write it down. Press the OUTPUT ON/OFF key to disable the output. 
3.  Move DMM leads to the B module terminals 6 and 7.  Press the OUTPUT ON/OFF key to 
enable the output. Measure the B module output and write it down, Press the OUTPUT 
ON/OFF key to disable the output. 
4.  Move DMM leads to the C module terminals 6 and 7.  Press the OUTPUT ON/OFF key to 
enable the output. Measure the C module output and write it down, Press the OUTPUT 
ON/OFF key to disable the output. 
5.  Move the DMM leads to the A module terminals 6 and 7 in the auxiliary cabinet. Press the 
OUTPUT ON/OFF key again to enable the output. Verify the phase A module output is 
within 50mVolts of the A module in the master cabinet. If it is not, adjust the pot behind the 
hole in the upper left corner of the module so the A output matches the A master output 
within 50mVolts. Repeat for the A’ module. Press the OUTPUT ON/OFF key to disable the 
output. 
6.  Move the DMM leads to the B module terminals 6 and 7 in the auxiliary cabinet. Press the 
OUTPUT ON/OFF key again to enable the output. Verify the phase B module output is 
within 50mVolts of the B module in the master cabinet. If it is not, adjust the pot behind the 
hole in the upper left corner of the module so the B output matches the B master output 
within 50mVolts. Repeat for the B’ module. Press the OUTPUT ON/OFF key to disable the 
output. 
7.  Move the DMM leads to the C module terminals 6 and 7 in the auxiliary cabinet. Press the 
OUTPUT ON/OFF key again to enable the output. Verify the phase C module output is 
within 50mVolts of the C module in the master cabinet. If it is not, adjust the pot behind the 
hole in the upper left corner of the module so the C output matches the C master output