Brooks Instrument 5851i - Manual (Page 7)

1-1
Installation and Operation Manual
X-TMF-5851i-MFC-eng
Part Number: 541B109AAG
September, 2009
Brooks ® Model 5851 i
Section 1 Introduction
1-1 Purpose
The Brooks ® Model 5851i Flow Controller is a mass flow measurement
device designed for accurately measuring and rapidly controlling flows of
gases. This instruction manual is intended to provide the user with all the
information necessary to install, operate and maintain the Brooks 5851i
Mass Flow Controller. This manual is organized into five sections:
Section 1 Introduction
Section 2 Installation
Section 3 Operation
Section 4 Maintenance and Troubleshooting
Section 5 Replacement Parts
It is recommended that this manual be read in its entirety before attempting
to operate or repair the Model 5851i.
1-2 Description
The Brooks Model 5851i Mass Flow Controller is used where manual,
electronic or computer controlled gas handling occurs. The Model 5851i
consists of three basic units: a flow sensor, a control valve and an integral
electronic control system. This combination produces a stable gas flow,
which eliminates the need to continuously monitor and re-adjust gas
pressures. Standard features include:
Fast Response Control permits rapid gas settling times with little or no
over/undershoot. Refer to Figure 1-1.
Soft Start provides a flow ramping function which slows down the
introduction of the process gas for those processes which cannot tolerate
rapid flow transition. Refer to Section 2-7 and Figure 1-2.
Valve Override permits the user to fully open and close the control valve
independent of the setpoint (command) setting. Refer to Section 2-6.
Setpoint (Command) permits the user to program the mass flow controller
with an external 0-5 Vdc or 4-20 mAdc signal. Refer to Section 2-6.
Low Command Valve Inhibit (Auto Shutoff) prevents the valve from
opening whenever the set-point is less than 2% of full scale.
Removable Cleanable Sensor permits the user to clean or replace the
sensor. Refer to Sections 4-2 & 4-4.
Output Limiting prevents possible damage to delicate data acquisition
devices by limiting the output to -0.7 Vdc and +6.8 Vdc on the voltage
signal output and 0 to 26 mA on the current output.