Browse Prior Art Database

Monitor for Mass Flow Controller Function

IP.com Disclosure Number: IPCOM000120721D
Original Publication Date: 1991-May-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 1 page(s) / 42K

Publishing Venue

IBM

Related People

Buchan, NI: AUTHOR

Abstract

Disclosed is a device that monitors the primary voltages present on commonly used Mass Flow Controllers (MFC).

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 99% of the total text.

Monitor for Mass Flow Controller Function

      Disclosed is a device that monitors the primary voltages
present on commonly used Mass Flow Controllers (MFC).

      It is often difficult to determine the failure mode of mass
flow control systems.  The failure may occur in the MFC, its control
unit, or the continuity may be interrupted in the cable conducting 14
analog signals between the two. The ability to monitor the MFC
function is crucial in trouble-shooting the failure mode of the
system.  An initial understanding of system function may be obtained
by monitoring the four vital analog voltages present at the MFC; the
power supply voltages (+15 VDC) and set point (0-5 VDC) supplied to
the MFC by the control unit, and the feedback voltage (0-5 VDC)
returned to the control unit.  As shown in the figure, an MFC-mounted
three port adapter (A) has been developed that allows all 14 analog
voltage lines to pass from the control unit (B) through the adapter
and to the MFC(C).  The adapter accommodates commonly used MFC units
manufactured by Sierra 1, Tylan 2, and MKS 3.  A failure is diagnosed
by plugging a specially adapted high impedance digital voltmeter (D)
into the adapter to monitor the four analog voltages discussed above.
Hence, the basic function of the MFC, its control unit, and the
connecting wire between, may be obtained.
1. Trademark of Sierra Instruments, Inc.
2. Trademark of Tylan Corporation
3. Trademark of MKS Instruments, Inc.

      Disclosed...