KEPCO KLP Series Developers Guide, Rev 3 - Manual (Page 98)

8-4
KLP-DEV 041213
8.2.2.4 ISOLATING RS 232 COMMUNICATIONS PROBLEMS [STANDARD MODELS ONLY]
A Loop Back test can be run from the KLP front panel to aid in isolating RS 232 communications
problems.
1. With the power supply in local mode, if the status display shows SET, tap either the CUR-
RENT or VOLTAGE controls to take the unit out of setpoint mode (status display goes from
SET to blank)
2. Use a thin tool (e.g., a paper clip), to press the FUNCTION switch repeatedly until the status
display shows UTIL. Press the DC OUTPUT switch to enter the Utilities menu. Rotate either
the VOLTAGE or CURRENT control until the status display shows LBT (Loop Back Test). At
this point the VOLTS display will show ----.
3. With the power supply's RS 232 port open (no connections), press the DC OUTPUT switch
once to run the test. The VOLTS display should show FAIL; if it reads PASS, the power sup-
ply is defective and requires repair.
4. Install the loop-back test connector (P/N 195-0112) at the RS 232 port, located on the rear
panel of the power supply. (If the loop back test connector is not available, install a jumper
from pin 2 to pin 3 of the RS 232 port connector.) Press the DC OUTPUT switch once to
rerun the test. The VOLTS display should now read PASS; if it reads FAIL, the power supply
is defective and requires repair.
5. To test the integrity of the cable assembly connecting the power supply RS 232 port to the
computer, remove the loop back test connector or jumper and connect the cable in its place.
Install a jumper wire from pin 2 to pin 3 at the opposite end of the cable and repeat the test of
(step 4) above. If the VOLTS display reads FAIL, the cable is either the improper type (not
null modem) or defective. If the VOLTS display reads PASS, the cable is correct. Remove the
jumper and reconnect the cable to the computer.
6. To exit the utilities menu, press the FUNCTION switch repeatedly until the status display is
blank.
If each of the above steps is completed successfully, the problem lies in the computer hard-
ware and/or software. Refer to the Product Support area of the Kepco website for additional
information regarding RS 232 Communications problems: www.kepcopower.com/support.