Agilent Technologies E4370A Measurement Capability, Voltage Measurements, Current Measurements

General Information - 1

The maximum power required for such a system is 25.6 kilowatts. A single power source of sufficient total amperage may be shared among multiple mainframes connected to the power bus, provided the total current can be provided while meeting the 24 volt dc input requirement at the power bus terminals on the rear of each mainframe. Multiple paralleled 24 volt dc sources may be used in place of the single 24 volt, 25.6 kilowatt dc source shown in the figure.

To achieve improvements in energy efficiency, the Agilent E4370A MCCD system can re-use discharge energy to supplement the energy provided by an external power source when charging other cells in a multi-unit system. This is possible because of the bi-directional power transfer capability between charging and discharging cells when connected to a common power bus. To take advantage of this energy transfer requires that some mainframes in the system must be operating in discharge mode at the same time that others are operating in charging mode.

No special control system is required for this configuration. The regulation circuits of the 24 volt dc power source, the Agilent E4370A MCCD, and Agilent E4371A Powerbus Load will operate properly without any special hardware control lines or additional software being required.

NOTE: Adequate size power bus wiring is required to carry high currents. Refer to Table 2-5.

Measurement Capability

The Agilent MCCD mainframe and charger/discharger cards have a high speed scanning system that makes voltage and current measurements on all channels. Refer to Appendix A for technical data about the measurement system. The following measurements are available:

Voltage Measurements

The Agilent MCCD measures the voltage of each channel using a calibrated internal measurement circuit. In local sensing mode, the voltage measurement is made at the power connector. In remote sensing mode, the voltage is measured at the end of the remote sense leads. The advantage of remote sensing over local sensing is that when the remote sense leads are connected to the cell, the actual voltage of the cell will be measured. Any voltage drops in the load leads will not affect the measurement. Refer to chapter 2 under Remote Sensing for more information.

NOTE: If your Agilent MCCD system is configured for local sensing, the measured output voltage may not reflect the actual voltage at the cell. This is because any voltage drops in the wires due to wire resistance, probe resistance, connector resistance, etc. will reduce the available voltage at the cell.

Current Measurements

The Agilent MCCD measures actual current in the output current path for each channel using a calibrated internal measurement circuit.

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