Agilent Technologies 667xA, 665xA Unregulated Operation, Saving and Recalling Operating States

Unregulated Operation

If the power supply goes into a mode of operation that is neither CV nor CC, the Unr annunciator will light. An unregulated condition limits the output current to a value that is safe for the power supply. Some unregulated states occur so briefly that they do not turn on the Unr annunciator, but they may set the UNR status bit during remote operation (see the power supply “Programming Guide”). One condition that can cause a noticeable unregulated state is low ac line voltage.

Saving and Recalling Operating States

You can save programming time by storing up to 5 (up to 4 with Series 668xA supplies) operating states in nonvolatile memory. The front panel programming parameters that are saved are:

■Output voltage, Output current, OVP voltage.

■ OCP state (on or off), Output state (enabled or disabled).

Note More power supply parameters are saved in remote operation. See the power supply “Programming Guide”.

As an example, set up the following state:

■Voltage = 4 V Current = 5 A OVP voltage = 4.5 V.

■ OCP = on (OCP annunciator on) Output = off (Dis annunciator on).

Save the above state to location 1 by pressing . Now set up the following state:

■ Voltage = 4.5 V Current = 2.5 A

■OCP = off (OCP annunciator off)

OVP voltage = 5 V.

Output = on (Dis annunciator off).

Save the above state to location 2 by pressing .

Restore the first state by pressing and verify the parameters. Restore the second state by pressing

. Note how the power supply is automatically programmed each time.

Turn-On Conditions

Whenever you apply power to a new power supply it automatically turns on in a safe reset state with the following parameters:

off 0 minimum* maximum off

*Minimum is the *RST value specified in Table 3-1 in the Programming Guide.

It is recommended that you leave the turn-on conditions as programmed. However, you may change them if you wish. To do this, proceed as follows:

1.Set up the power supply to the state you want when it is turned on.

2.Store that state to location 0.

3.Turn off the power supply.

4.Hold in the key and turn the power supply back on. The display indicates RCL 0 PWR-ONto verify that the power

supply has configured its turn-on state to that stored in location 0.

5. From now on the supply will always turn on to the state defined in location 0.

92 Front Panel Operation