Mass Flow Control & Metering

Florite International’s microcomputer-based, programmable instrumentation plays a critical role in the control and metering of Mass Flow processes.

A Mass Flow Controller automatically controls the flow rate of a gas according to a set rate sent as an electric signal, without being affected by conditions or changes in gas pressure. MFC’s are an indispensable part of automated production lines when accurate control of flow rates is required. Some processes require very small flows (measured in sccm) while others handle higher flows (measured in slpm). Industries such as Semiconductor, Biopharmaceutical, Petrochemical typically utilize MFC’s as part of their manufacturing and R&D processes.

What’s Inside

MFC diagramMass flow controllers have a flow rate measurement compartment that includes a sensor, a bypass, a flow rate control valve, and special circuitry.

The gas input is divided so that it flows over both a flow rate sensor and a bypass. The sensor measures the mass flow rate of the gas, and the flow rate control valve modifies the flow rate so that the difference between the measured flow rate and the flow rate received from the external flow rate setting signal is 0.

MFC’s feature a loop circuit, so even if there is a pressure or ambient temperature change that could affect the supply pressure of the introduced gas, the flow rate is instantaneously corrected which ensures stable flow rate control.

In order to control the process, you must be able to precisely measure what is happening at every point along the path of the flow. And then be able to use those measurements in real time to keep the process on target.

The Missing Component

There is one critical component that is not included: a Power Supply, Readout and Set Point Controller. Florite’s four-channel 990X-MFC and single-channel 991R-MFC serve this vital role as a Human Machine Interface (HMI) and multi-purpose companion to the Mass Flow Controller. In addition to supplying power, these two units generate flow setpoint commands, display flow rates, totalize flows, blend multiple flow streams, and more.

Florite 990X-MFC multi-channel

990X MFC Home Screen


The 990X-MFC and 991R-MFC supply a power range of -15V to +24 Vdc power depending on the requirements of the MFC.


Both units feature high contrast, backlit graphic displays which allow users to view real-time process variables and the programmed set point for each connected device right from the home screen. This enables the user to rapidly identify and make in-process adjustments in seconds. Audio and visual indicators provide immediate status information for rates and diagnostic operating conditions.

Set Point Control

The user-friendly interface allows for intuitive navigation as each channel displays both Set Point (SP) and Process Variable (PV) values. The desired SP value is dialed in on one line while the other shows the PV as it is being measured in real time. Adjustments can be made on the fly and all four channels can be monitored separately on one screen. The value displayed on each channel can be independently set for percent full scale or engineering units to display flow rate, pressure, density, or temperature.


Florite 991R-MFC single channel

991R MFC Home Screen


• Generate flow setpoint commands
• Display flow rate or pressure
• Totalize flow for inventory management
• Batch control for single or multi-channel batch recipes
• Support master-slave blending configuration and operation



• Valve Override Control (VOR) allows rapid purge or chamber flooding from the keypad
• Programmable gas Sensor Factor adapts any mass flow device to virtually any fluid application
• RS232 port provides a remote readout, set point, control, and data acquisition via serial communication
• Built-in diagnostic tests support easy installation and assist in ensuring a long, trouble-free operating life

From batching to blending to dosing control, Florite’s MFC Power Supply, Readout and Set Point Controllers are powerful tools that are designed to work seamlessly with today’s most advanced Mass Flow Control Instrumentation. Contact Florite today to discuss Private Labeling opportunities.

990X-MFC Multi-Channel Specification
991R-MFC Single Channel Specification