MKS T3PIA, Instruction Manual, Page: 17 / 70

Introduction Chapter One: General Information
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Chapter One: General Information
Introduction
The MKS Type T3P Throttle Valve is designed for use in downstream pressure control applications.
The T3P unit consists of a throttling isolation valve with an electronic housing attached to the motor plate, a
microprocessor, driver circuits which eliminate the need for a separate controller box, the RS-232 serial
communications interface, and analog outputs that reflect pressure or valve position. The valve is controlled
by using digital values sent through the serial network.
The operation of the controller is based on a digital pressure/position control algorithm that directs the valve
to the proper position for either pressure or position control. The pressure or position setpoint is sent as a
digital serial command. The T3P unit reads the pressure signal used for control applications directly from an
MKS Baratron pressure transducer. All of the unit’s operational settings are controlled using the serial
communication protocol.
When the T3P controller is turned off or experiences an unexpected power loss, all calibration constants are
saved in non-volatile memory.
Protection from RF interference and noisy electrical environments is increased by the use of a metal case, by
internal design elements, and by the use of surge and ESD suppression networks and RFI filtering on all
inputs and outputs. The T3P unit meets the testing standards required for the European CE Mark when used
with an overall metal braided shielded cable, properly grounded at both ends.
Definitions
Table 5: Definitions
Term Description
Full Scale (FS) Range The defined 100% value of an attribute, in its assigned units
Sccm Standard cubic centimeters per minute
Setpoint The pressure value to which the device is controlling the flow of gas
Slm Standard liters per minute
Trip Point An alarm or warning level