DH Instruments MFC SWITCHBOX, User Manual

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1. INTRODUCTION
Page 1 © 1997-2008 DH Instruments, a Fluke Company
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1.1 PRODUCT OVERVIEW
The MFC Switchbox™ can be used to connect a molbox1™ MFC control option or an MFC-CB™ control
channel to up to five MFCs, or to one MFC and four MFMs. The rear panel of the MFC Switchbox
connects to the molbox1 or MFC-CB via a circular 5-pin connector and a 25-pin DSUB connector.
Cables are provided with the switchbox to facilitate these connections. A power cable is also provided.
The MFC Switchbox contains its own power supply which allows it to maintain continuous power on all
five devices under test (DUTs). The MFC Switchbox provides up to 55 watts of power. This allows it to
provide 260 mA per MFC when fully loaded. MFCs typically require a maximum of 200 mA. Therefore,
all five ports of the MFC Switchbox can be used simultaneously in most situations. Occasionally, when
calibrating older, power hungry MFCs, it may only be feasible to connect four MFCs at a time.
The front panel of the MFC Switchbox has five 25-pin DSUB connectors. These connectors are used to
connect the switchbox to the various DUTs.
Current controlled MFCs can only be used on channel 1. When testing MFMs, an MFC can be used for
controlling the flow in the test while taking the measurement data from the currently selected MFM.
This controlling MFC must be a voltage based MFC.