Calibration Procedures

Introduction

This appendix discusses the software calibration procedures for the power supply. These supplies should be calibrated annually or whenever certain repairs are made (see Service Manual).

Because there are no internal or external hardware adjustments, your power supply can be calibrated without removing the covers or removing it from the cabinet if it is rack mounted. Calibration is performed by measuring actual output values and sending them to the supply over the GP-IB. The power supply uses these values to calculate output, readback, and overvoltage correction constants. These correction constants are stored in a non-volatile memory on the GP-IB interface board of the supply. Thereafter, when a command such as ’’VSET1,5" is sent to set the voltage on output 1, the power supply uses the correction constants to accurately program the output.

Correction constants for offset and full scale voltage and current values are stored for one output channel at a time. A separate calibration command calculates and stores correction constants for the internal overvoltage circuit. This appendix lists the equipment that you need, shows the test setup to perform the calibration, gives a general calibration procedure that explains all of the calibration commands, and gives a sample program you can use if you have an Agilent 3456A voltmeter and an HP Series 200/300 computer with BASIC.

Security against accidental calibration is available. A jumper inside the unit may be moved to disable all calibration commands. Access to this jumper requires opening the unit (see the Service Manual).

Tables A-1 and A-2 give the data ranges for all of the power supply calibration commands. Refer to Figure 5-2 for the syntax structure of the calibration commands. You can either execute the calibration commands directly from the keyboard, or you can use them in a program to reduce the time involved in calibrating each output.

NOTE	The memory used to store correction constants will accept and store data about 10,000 times, which is
	more than sufficient for normal calibrations over the life of the instrument. However, do not put the unit
	in a calibration loop that repeatedly turns the calibration mode on and off.

Test Equipment and Setup Required

The following test equipment is required for calibration:

1.A computer connected to the GP-IB connector on the back of the power supply.

2.A voltmeter accurate to 0.003% of reading.

3.A precision 0.1 Ω, ± 0.05%, 10 amp shunt resistor (4 terminal).

Figure A-1 shows the setup required for calibrating both voltage and current. Observe polarity when connecting the voltmeter. Note that for voltage calibration, the voltmeter leads are connected to the + S and - S terminals and NOT the + V and - V terminals. Note that for both + and - current calibration the voltmeter leads are connected to the shunt resistor’s sense terminals.

Calibration Procedures 89

6627A, 6621A, 6624A, 6623A, 6622A specifications

Agilent Technologies is renowned for its high-quality electronic test and measurement equipment, and the Agilent 6600 series is no exception. This series includes models like the Agilent 6621A, 6622A, 6623A, 6624A, and 6627A, each designed to meet the needs of various application requirements, making them an essential part of modern laboratories.

The Agilent 6621A is a single-output DC power supply that provides a stable output voltage and current, making it ideal for testing and powering electronic devices. It features a low noise specification, which is crucial for sensitive applications. With a maximum output voltage of 30V and a current of 3A, it offers flexibility for a range of projects, from powering prototypes to performing benchmark tests.

The Agilent 6622A, a dual-output model, enhances versatility by allowing users to power two devices concurrently. It delivers output voltages of up to 20V and a total output current of 5A, which is perfect for powering circuit boards with multiple components. The built-in voltage and current limiting functions protect the equipment under test, preventing any potential damage.

On the other hand, the Agilent 6623A provides additional capabilities with its three outputs, making it particularly suitable for complex testing procedures. With a maximum voltage of 20V and output current reaching 6A across all channels, it ensures that multiple loads can be powered simultaneously without compromising performance.

The Agilent 6624A further pushes these capabilities with its higher output power. This model boasts two outputs with a combined maximum output of up to 6A, supporting devices that require more demanding power levels. Its advanced control features allow for precise voltage and current adjustments, enhancing reliability during experiments.

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All models in the Agilent 6600 series incorporate built-in protection features to guarantee safety during testing. They are equipped with memory functions, allowing users to save and recall settings quickly. Additionally, the intuitive interface and various connectivity options make these power supplies user-friendly, ensuring efficient workflow in any laboratory setting. In summary, the Agilent 6600 series offers a compelling combination of versatility, precision, and advanced features, catering to diverse electronic testing applications.