Setpoint ramping tutorial

Alicat controllers come equipped with a setpoint ramping feature that allows them to ramp up and/or down to changes in setpoint. With setpoint ramping, you can set a maximum speed at which a mass flow or pressure controller flows until the setpoint is achieved. Setpoint ramping can be performed using either the front display or serial commands.

Setpoint ramping is commonly used to ensure safety, by ramping up pressure or flow in a controlled, observable way. Setpoint ramping can also be configured to only apply to flow/pressure in a single direction for situations where you may need to quickly zero pressure or flow during an emergency.

To enable and edit the setpoint ramp functionality on your device, follow the instructions below.

Video tutorial

Step-by-step instructions (front panel)

Press the bottom right button for “MENU” selection.
Press the top left button for “CONTROL” selection.
Press the top left button for “SETPT RAMP” selection.
Press the top left button for “DELTA” selection.
Use the up, down, and select digit buttons to set your desired delta.
Press the bottom right button for “SET” selection.
Press the top right button for “TIME” selection.
Use the up, down, and select digit buttons to set your desired time.
Press the bottom right button for “SET” selection.
Press the top middle button for “TIME UNITS” selection.
Use the up and down buttons to select your desired time units.
1. Note: This will NOT change the rate, and it will automatically update the current rate to the newly selected units.
Press the bottom right button for “SET” selection.

Video transcript

“My name is Marina Palese, and I’m an App Engineer at Alicat Scientific. Today I’m going to show you how to set up setpoint ramping. Let’s get started.”

To give a setpoint ramp to your device, we’re going to to MENU (bottom right button), CONTROL (top left button), SETPT Ramp (top left button), and from here we can set our DELTA (top left button). This is how much we want the flow to change in this ramp, and we can set that to whatever value we like (ex. 100 SLPM).

At this point the display will read “Current Max Ramp Rate -None- SLPM/s”.

The TIME (top right button) will be the amount of delta over time. Let’s say we want to change 100 SLPM per one second.

At this point the display will read “Current Max Ramp Rate 99.99999 SLPM/s”.

And then we can set out units (top middle button). Let’s say we change these to hours. Then, the current ramp rate will automatically adjust to whatever the time unit is.

Finally, the display will read “Current Max Ramp Rate 360000 SLPM/hour”.