MKS Type 640B Electronic Absolute Pressure Controller 100 torr, 1000 sccm, 1/4 in Swagelok, Viton, PN 640B12TS1V22V
The 640B are self contained, compact, closed-loop
electronic pressure control systems. They contain a capacitance manometer, normally closed
proportioning control valve, and closed-loop control electronics. The 640B controls
absolute pressure. A 641B pressure gauge controller is also available and measures pressure relative to ambient barometric
pressure. Pressure Range for this unit is 100 torr, 1000 sccm/1 slm flow, min range 2% of full range to 2 torr, 1/4'' Swagelok® connections and Viton Seals.
Swagelok is a registered trademark of The Swagelok Company.
The transducer is a Baratron capacitance manometer, with Full Scale
pressure ranges from 100 psi to as low as 10 Torr. Baratron capacitance manometers –
well-known for their percent of reading accuracy, stability, and resolution – provide precise
measurements at lower pressures and over wider dynamic ranges than strain gauge
transducers. Furthermore, Baratron capacitance manometers have no silicone oil fill which
can result in hysteresis and can slow the controller time response.
Electrically similar to a standard Mass Flow Controller, the 640B are powered by ±15 VDC at only 200
mA, permitting use with standard power supply/display electronics such as MKS 246 or 247 Power Supplies.
The pressure output and input control signals are linear 0-5 or 0-10 VDC. Two trip points are included in the 640B
with LED status indicators, for use as simple on/off process limits.
During final testing at MKS, the 640B control loop tuning parameters are preset for
typical installation conditions, but are field adjustable for different conditions and optimum
performance. The Proportional and Integral Term adjustments are simple rotary switches,
rather than potentiometers, to enable OEMs, or users with multiple controllers, to preset all
units to the same control loop parameters.
NOTE: For Valve Orifice Size and Pressure Range for your application please see MKS 640B 641B Brochure.pdf Page 2 to the side at Downloads.