1.0   Functional Test Procedure

PURPOSE: This procedure outlines the steps to functionally test the Back UPS CS350/CS500/CS350EI/CS500EI/CS350TW/CS500TW.  The functional test is broken down into several sections which test for a particular function of the UPS.  Sections include tests for power capacity, run time, transfer levels and battery charging.  Units which are not functioning properly should be serviced.

1.1   Phase synchronization test

1. Plug the variac into the AC line and set the variac output  voltage per Table 1.

Table 1.

2.         Plug the UPS into the variac and turn the UPS on.

3.         Using an oscilloscope, monitor the UPS output voltage.

4.         Turn off the variac.  The UPS should immediately transfer to backup power (while on battery the UPS's output is a stepped approximation to a sine wave with the correct peak, and rms values).  Dependent on the last on line frequency seen by the UPS the output frequency should be 50 or 60 Hz on battery.

5.         Turn on the variac and observe the transfer from power inverter (stepped wave) to utility line (sine wave) on the oscilloscope. The stepped wave should lock into the sine wave and maintain phase synchronization. Repeat this test a few times to clearly observe the phase lock in action.

6.         If phase lock does not occur, the PCB should be replaced.

EXAMPLE

1.2   Transfer level test

1.         Plug the variac into the AC line and set the variac output voltage as stated in referencing Table 1.

2.         Plug the UPS into the variac and turn the UPS on.

1. Using true RMS voltmeters, monitor the output voltage of the variac and the output voltage of the UPS under test.

1. Slowly turn down the variac and monitor the UPS's output voltage.  The UPS should transfer to on battery at following lower transfer point voltages, refer to table 2.    Repeat this procedure a couple of times to ensure accurate results.

Table 2.

1. Turn the variac up so that the UPS goes back to on-line operation.

1. Slowly turn the variac up until the UPS transfers to on battery.  The UPS should transfer to on battery at the following upper transfer point voltages, refer to table 3.  Repeat this procedure a couple of times to ensure that the results are accurate.

Table 3.

7.         If the UPS does not transfer properly, the UPS should be serviced.

1.3   Short circuit test

This test requires a short box.  The purpose of this test is to ensure that the UPS will disable it's output in the presence of a short.

1. 1.             With no loads attached to the output of the UPS, cold boot the UPS by pressing the front panel switch for approximately 2 seconds and after the UPS has emitted a constant tone, release switch.  UPS should provide output power to the battery back up outlets.

2.         For this test, only plug the short circuit box into the UPS’s battery back-up outlets. (Warning: switch should be in the OPEN circuit position).

1. Using an oscilloscope, monitor the output waveform of the UPS.

1. Close the switch on the short circuit box (short circuit the UPS’s output).

1. The UPS should emit a continuous tone within a second and the UPS should shut off due to an overload.  For the duration of this event, oscilloscope should indicate that there is no output from the UPS. This indicates that the UPS's power inverter has shut down.

1. Remove short box from UPS’s battery back up outlets.

1. If the output was not disabled, the PCB should be replaced.

1.4    Backup Capacity Test

1. Prior to performing this test the unit should be charged for at least 12 hours.

1. Plug the variac into the AC line and set the variac output voltage as stated in Table 1.

1. Plug the UPS into the variac.

1. Turn UPS on.

1. Connect a true RMS voltmeter to the output of the UPS. 

1. Connect Full load to the output of the battery back up outlets.  Refer to Table 4.

Table 4. Ratings for full load power.

1. Unplug the UPS from the variac so that the UPS will operate on battery.

1. The load should remain powered.  Using the voltmeter, confirm that the output voltage is within the following ranges listed in Table 4.

Table 5.  Output voltage ratings for on battery operation

9.         If the UPS does not support the load, The UPS should be serviced.

1.5    Battery Reserve Time Test

1.     Prior to performing this test, the UPS should have been plugged into a working utility line for a minimum of 12 hours and the UPS's batteries should be fully charged.

2.      Plug the variac into the AC line and set the variac output voltage as stated in Table 1.

3.     Plug the UPS into the variac.

1. Connect a true RMS voltmeter to the output of the UPS.

1. Turn UPS on.

1. Use  Table 6 and 7 to determine the correct size of a load to plug into the UPS.  Plug the appropriate load into the UPS.

Table 6.  Approximate runtimes at 25 degrees C

Table 7.  Approximate runtimes at 25 degrees C

7.     Unplug the UPS from the variac so that the UPS will operate on battery.

        Using a stopwatch, time how long the UPS maintains power to the load.  The UPS will continue to run without an audible alarm until a low battery condition is reached.  The UPS beeps continuously (usually every  minute) until it shuts down from battery exhaustion.  The expected runtimes at full load can be seen in Tables 6 and 7.  These values may be slightly less if the batteries are over one year old.

8.     Charge the UPS for at least 12 hours before storing or using the UPS.

9.     If the UPS does not last the minimum run time, the battery may need to be replaced.

1.6    Computer Interface Port Test

The Back-UPS CS350/CS500/CS350EI/CS500EI/CS350TW/CS500TW are equipped with a 10 pin RJ45 connector to allow for communication between the UPS and a host computer.  This communication port can be used for either USB communication or simple signaling communication.  It is important to note that there are two separate cables for these communication protocols. A detailed description of the port can be found in section 1.7. The following steps should be performed to ensure the interface port is working properly.

1.       Plug the variac into the AC line and set the variac output voltage as stated in Table 1.

2.       Plug the UPS into the variac.  Turn on the UPS.

For simple signaling testing:

3.        Using a multimeter, measure the voltage between pins 2 (+ probe) and 4 (- probe) on connector.  The voltage should be at zero volts.      

4.       Unplug the UPS from the variac so that the UPS operates on battery.  The DC voltage between pins 2 and 4 should now be a HI RS-232 level( +3 - +15 Vdc).

1. 5.              While the UPS is operating on battery, apply a HI RS-232 signal to pin 8 of the connector by shorting pin 2 to pin 8 for a minimum of 10 seconds.   The UPS should shut off.

1. 6.              Remove the short between pins 2 and 8.  UPS should power back up after it is plugged back into variac.

For USB communication testing:

1. 7.              While the UPS is on, connect the USB cable to the host computer from the 10 pin connector.

1. 8.              Using a DVM, measure pin 1(Vcc) referenced to pin 7 (USB signal ground) of the 10 pin connector.  The voltage should be approximately +5 volts.

1. 9.              Using an oscilliscope, measure pin 9 referenced to pin 7.  Set scope to 1 volt per division.  There should be a 0 to +3.3V bi-directional signal present.  This is one of the two communication signals. 

1. 10.           Using an additional scope probe set to the same volts per division as stated in 9., measure pin 10 referenced to pin 7.  There should be a 0 to + 3.3V bi-directional signal present.  This is the remaining communication signals

11.     If the UPS fails any of the above tests, the PCB should be replaced.

1.7    Computer Interface Port Description

The Back-UPS CS350/CS500/CS350EI/CS500EI/CS350TW/CS500TW models have an RJ-45 10 pin communication port which may be connected to a host computer system for either simple signaling or USB communication.  The USB cable is provided with the UPS but it is necessary to purchase the simple signaling cable separately.  This port allows the computer to monitor the status of the UPS and in some cases control the operation of the UPS.  Below is a detailed description of each of the serial port's pins:

Table 8:  Communication port pin descriptions

1.8    Battery Charger Test

1. 1.     Plug the variac into the AC line and set the variac output voltage as stated in Table 1.

1. 2.     Plug the UPS into the variac.

1. 3.     Disconnect battery from unit.

1. 4.     Using a DVM, measure the DC voltage across the batteries red and black wires.

1. 5.     The voltage should be 13.7 VDC +/- 1%.   Minimum 13.563V, Maximum 13.837V

1. 6.     If the battery charger voltage is not within range, the PCB should be replaced.