Note: These instructions are revised from those originally submitted.

Appendix L: User's Manual

Description

The Push-Button Power supply has three different power supply units: a variable 35V unit, a fixed 15V unit, and a fixed +5V unit. Each unit is separately fused, and completely independent. The variable unit can be set to output a desired voltage or current, and is constantly monitored to ensure proper operation. The fixed units are monitored to provide constant voltage.

• Do not use near water!
• Keep out of reach of small children!
• Do not short output leads!
• Always wear proper eye protection when using device!
• Read the instruction manual completely before operating the device.

Instructions

Turning the unit on and off

• Ensure that no two output sockets are shorted together.
• Switch the ON/OFF button to the desired position. The ON/OFF button is located on the front panel of the power supply.
• Characters should be seen on the display. If the display does not come on when the switch is in the ON position see "Troubleshooting."

Enabling and disabling the output

• If the display shows "Stopped" in the lower left hand corner, the outputs are disabled. Press the START/STOP button to enable the output. The START/STOP button is located on the lower left of the keypad.
• If the display shows "Running" in the lower left hand corner, the outputs are enabled. Press the START/STOP button to disable the output.

Setting a voltage or current

A voltage or current can be set for the variable supplies any time the power supply is on. The settings only take effect while the outputs are enabled (see "Enabling the output.") If too high a voltage is requested by the user the variable supply will output the maximum rated voltage. If too high a current is requested by the user, the variable supplies will return an error message (see "Resolving Errors.") A load must be present on both the positive and negative half of the variable supply before attempting to set a current or error conditions will occur.

• Use the V/I button to select either voltage or current control. The display will show a "V" for voltage or an "I" for current in the middle of the bottom line of the display. If the proper state is already shown, the V/I key does not need to be pressed.
• Type in the desired value using the numeric keys. If needed, the BS key will erase the last character typed, and the CLR key will clear the input. The input is shown on the lower right of the display.
• Press the key. The input value should disappear from the display and the variable supplies should adjust to the input values if the outputs are enabled (see "Enabling and disabling the output.") If an error message occurs, see "Handling errors."
• Pressing the key while the input value is blank will set the variable supplies to 0V or 0A, depending on the setting of the V/I key.

Handling Errors

Four errors can occur on the power supply: over voltage, under voltage, over current, under current. Whenever an error occurs the outputs are automatically disabled. An error message will appear on the display and the warning light will come on. The error message is shown in Figure 15.

Variable 1 - Negative polarity
OVER VOLTAGE
Press CLEAR to change settings,
or START/STOP to try again.

The error message will include the affected supply (VARIABLE 1, FIXED +/-15, FIXED +5), the effected polarity (POSITIVE, NEGATIVE), and the proper error (OVER VOLTAGE, UNDER VOLTAGE, OVER CURRENT, UNDER CURRENT) in the displayed message. Over voltage errors are often a result of too high an impedance for the supply to generate the desired current through, or else an internal problem has developed in the supply. Under voltage errors imply that the fixed supplies are being used with too low an impedance. Over current errors often indicate a short circuit or low impedance situation for the variable supply. Under current errors suggest that an internal error has occurred in the supply.

• Check the circuit connected to the supply with the error. Ensure that the circuit does not have errors.
• Press the START/STOP key to retry with the same settings, or press the CLR key to adjust the settings before trying again.
• If errors continue to occur and the circuit is correct see "Troubleshooting."
• Do not ignore error messages or damage to the supplies or to connected circuits may result.

Troubleshooting

Any other problems, and these problems if not resolved by following the suggestions, should be referred to trained personnel.

• DO NOT OPEN THE UNIT FOR ANY REASON! There are no user serviceable parts on the inside of the unit.

Electrical Specifications