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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 HP-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 HP-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 a HP 3456A voltmeter and a 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 HP-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.

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HP 6621A, 6623A, 6624A manual Calibration Procedures, Test Equipment and Setup Required
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6624A, 6621A, 6623A specifications

The HP 6623A, 6621A, and 6624A are precision DC power supplies widely recognized for their reliability and performance in various laboratory and industrial applications. These models are part of HP's 662X series, designed to cater to the needs of engineers, researchers, and technicians who require accurate power sources for their testing and development activities.

The main features of the HP 6623A, 6621A, and 6624A include their high stability, low ripple, and excellent load regulation, ensuring that the output voltage and current remain stable during testing. The power supplies provide multiple output channels, allowing users to power multiple devices simultaneously. The flexibility in setting voltage and current levels makes these models ideal for a wide range of applications, including semiconductor testing, device characterization, and system integration.

One of the standout technologies in the HP 662X series is the use of smart design techniques that minimize noise and enhance output performance. These power supplies incorporate advanced feedback mechanisms to maintain steady output, even under varying load conditions. Additionally, they feature programmable outputs, which means users can adjust the output levels through a connected computer or control system, streamlining the testing process and improving efficiency.

The HP 6623A model offers three independent outputs, with total power capabilities of 40 watts. It includes a 0-20V output, which can deliver up to 2A of current, along with two additional outputs that are adjustable. The 6621A provides a single output option, delivering a maximum of 20V and 2A, making it well-suited for simple applications where a single power source is required. In contrast, the HP 6624A stands out with its four independent output channels, providing a total of 60 watts, making it the most versatile of the three models.

Characteristics of these power supplies include user-friendly interfaces, allowing for easy configuration and monitoring of settings. LED indicators provide real-time feedback on voltage and current levels, enabling users to quickly assess the performance of their tests. Moreover, built-in protection features safeguard both the power supply and the connected devices from overvoltage and overcurrent conditions.

Overall, the HP 6623A, 6621A, and 6624A power supplies embody advanced engineering and design, making them invaluable tools for professionals looking for high-quality, reliable power sources for their electronic testing needs.
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