Video Library

Alicat Video Library

How the gas totalizer on a mass flow controller works

Mass flow totalizing is used for measuring how much accumulated mass of a particular gas (or gas mixture) has been flowed in a process, where a meter alone will measure the rate of flow at any given moment. Alicat mass flow meters have a totalizer function option, which can be great for monitoring processes.

On a mass flow controller, the totalizer option can be used to dispense a set amount of gas, since the controller is equipped with a high precision, fast-response valve. Mass totalizer dispensing is used in bio-reactors, micro-flow dispensing in pharmaceutical testing and production, fermentation, and even high altitude ballooning. This video is a how-to navigate the menus using the built-in display and user interface for changing parameters and resetting the totalizer. Alicat mass flow instruments can also be controlled through serial communications or industrial protocols.



Step-by-Step Instructions

Understanding how to tare your Alicat device

What is tare? Why is it important? And how do I tare?

Setting the tare takes a sensor signal and sets it as zero in flow or pressure. A zero setpoint results in closing of the valve (on controllers, not meters) and creates a known “no flow” condition. Tare makes readings more accurate by removing cumulative errors from drift.

An analogy might be a bathroom scale. By getting on and then off a bathroom scale repeatedly over time, the needle may no longer return to pointing at zero. On mechanical scales, one could see this: with no weight on the scale, the pointer might point to more or less than zero. If it pointed to +1, and you weighed yourself, the reported number would be your actual weight, plus one—the scale would read your weight as heavier than it should (which is always unacceptable!) These scales had a small knob or dial, usually on the front or back bottom edge, to adjust the dial reading back to zero. But you would need to adjust the pointer only when there was no weight on the scale, or else you introduced an error.

Similarly, many measurement devices need to have tare set to remove this drift periodically. Improperly setting tare (when flow is occurring) of an Alicat instrument will result in inaccurate readings as well, since the flow that was occurring during the tare will be subtracted from the true reading.

This video shows how to set a tare manually using the display buttons, and how to turn on or off the Auto-Tare function, which tares the flow controller automatically whenever a 0 setpoint occurs.



Step-by-Step Instructions

Tuning the PD settings on your Alicat instrument

If you ever find your Alicat controller struggling to efficiently meet the desired setpoint, it may mean your PD settings need to be adjusted.

This video shows how to change your PD settings without having to send the device back to the factory; with options through FlowVision, terminal commands and directly on the controller itself available, Alicat assures your ability to change the settings quickly and easily.

Printable Directions


Fast control of gas mass flow and pressure over EtherNet/IP

Gas mass flow and pressure control using EtherNet/IP is a popular method of setting up an automated system. A drawback is that digital communications are notoriously slower than analog — and since we have the fastest mass flow controllers in the world, where’s the fun in getting slowed down?

Using a gas flow or pressure device with on-board EtherNet/IP means faster throughput than going through a translator device. So the whole process is faster. And still highly accurate. EtherNet/IP is also easy to implement, because the hardware uses standard EtherNet wiring and routers.

Consider Alicat also for: EtherNet/IP equipped devices for liquid flow control, gas metering and pressure gauges.

Standard Temperature and Pressure settings on a mass flow controller

Obtaining correlated data between instruments is essential, which is why we made it easy to change your Standard Temperature and Pressure designation on an Alicat mass flow controller (or mass flow meter) in the field. No need to send your flow controller or flow meter back to the factory when you change your chosen normal operating conditions, or have to match an Alicat to another instrument’s configuration.



This video shows how to change the STP settings using the display buttons and menus, but these settings can also be changed through serial communications like RS232 or RS485.

Printable Directions

Ask Alicat: How can I use a mass flow controller set to a pressure control PID loop?

Because Alicat MFCs are multivariate (they measure several things, like mass, volume and pressure at once), we built them to control on different things while still measuring mass.

So you can set an Alicat MFC to measure mass flow of gases, while controlling the pressure the gas is at in your process. Alicat Applications Engineer Alyssa Jenkins explains why that’s useful, and why it’s cool.

Ask Alicat: How do you communicate with your Alicat?

The Alicat is inherently a very feature-rich, multi-variant device that outputs a large amount of data. It’s not just a black box with a simple input and output—it provides useful data in many different ways.

Because of its versatility, it’s important to choose the kind of communication you want to perform with the device overall. The most basic would be to use the easy-to-read backlit LCD panel on the front of the device. To communicate with other devices, Alicat uses internet protocols, ethernet-based protocols, RS232, RS45, Modbus RTU, Modbus TCP/IP, DeviceNet, Profibus, EtherCAT, and analog signals like 4-20mA, 0-10 volt, or 0-5 volt.

Ask Alicat: How do Fiber Optics companies use Alicat instruments?

Making glass fiber optics, from preform fabrication on the lathe, through polymer coatings after drawing the glass is a high precision process.

That’s why Alicat instruments are favored among leading manufacturers, because Alicat works with the glass fiber manufacturer to optimize their processes, reduce costs and improve data collection.

Rolamite Valve Swap

This video shows how to change the position of a large Rolamite valve on an Alicat gas mass flow controller (part numbers beginning with MCR), from upstream to downstream. Moving the valve is done to place the sensor in a different location of the flow stream relative to the valve, because of differences in pressures and ranges. The procedure is reversible if you need to move the valve from downstream to upstream. It is essentially the same on a high-flow Alicat pressure controller (part number beginning with PCR). The procedure takes about 10 minutes. It is not highly technical, but is best performed by an experienced technician.

Printable Directions


If you have a flow or pressure controller with a smaller valve, see our video for changing a small valve.

Fast Flow Calibrations at Low Flow Rates Using A Mass Flow Meter

Tired of waiting for your slow positive displacement meter? Alicat’s flow meters run circles around PD meters, giving you instant readings even at the lowest flow rates. Do a 20-point MFC calibration in minutes, not hours, even at low flow rates such as 20 sccm or less.

This video features a battery-operated portable mass flow meter with NIST-traceable accuracy and instant-on technology. The Whisper™ line of flow meters has very low pressure drop. Flow faster, with less impact on your system.

Ask Alicat: How fast is your mass flow controller?

Flow stability and accuracy depend on fast control response, and Alicat has the fastest mass flow control stability specification. This video demonstrates 0 to 100% setpoint changes with settling times of less than 30 ms and a control time constant of only 7.4 ms. For fastest control speed of response, choose an Alicat mass flow controller.

Alicat Rolamite Valve Cleaning

This video shows how to disassemble, clean and reassemble an Alicat Rolamite valve. Should your valve require a higher level of cleaning or repair, please contact Alicat at 888-290-6060.

Ask Alicat: What Is Pressure Drop?

Pressure drop is the amount of line pressure that is permanently lost as gas passes through an instrument in a gas line. Alicat Scientific demonstrates the importance of pressure drop for gas flow processes and shows how you can greatly reduce pressure drop by using its Whisper Series of mass flow instruments. The Whisper Series includes mass flow meters and mass flow controllers. Both installed and portable versions are available.

How do you control mass flow in TWO directions?

Alicat Scientific introduces the world’s first bidirectional mass flow and pressure controller: the dual-valve MCD. Control mass flow, volumetric flow and pressure in both directions with stand-alone control and 30 on-board gas calibrations over a 200:1 turndown range. Or control pressure or flow into a closed process, and vent the volume with no need for additional bleed valves or continuous outgassing. The MCD is the single most versatile flow controller in the world.

Changing valve position on any small valve Alicat controller

How to change the valve position from upstream to downstream, or vice versa, on any Alicat mass flow controller or pressure controller that utilizes the Alicat small valve. This procedure will not apply to any Alicat controllers that utilize the medium or large valve. If you have a medium or large valve controller please contact Alicat for assistance.

Printable Directions


WordPress Video Lightbox Plugin