# Gasflow calculation for Learn

Navigation: Valve Firmware > Pressure Control > Adaptive algorithm > Learn > # Gasflow calculation for Learn |

| Do not apply a different gasflow for learn than determined below. Otherwise pressure control performance may be insufficient. Required pressure / flow regime must be known to calculate the most suitable learn gas flow for a specific application.

1.At first it is necessary to find out about the required control range respectively its conductance values. Each working point (pressure / flow) must be calculated with one following formulas. Choose the applicable formula depending on units you are familiar with.
Set the viscous correction factor k to 1 for molecular flow - p(wp) < 1 Torr, or to 2.5 for viscous flow - p(wp) > 1 Torr.

| C WP required conductance of working point [l/s] q WP gasflow of working point [Pa m3/s] p WP pressure of working point [Pa] k viscous correction factor

| C WP required conductance of working point [l/s] q WP gasflow of working point [mbar l/s] p WP pressure of working point [mbar] k viscous correction factor

| C WP required conductance of working point [l/s] q WP gasflow of working point [sccm] p WP pressure of working point [Torr] k viscous correction factor

2.Out of these calculated conductance values choose the lowest.

| C R required lower conductance [l/s] C WPx required conductance of working points [l/s]
| To make sure that the valve is capable to control the most extreme working point verify that CR ≥ Cmin of the valve (refer to «Technical data»).

3.Calculate gasflow for learn. Choose the applicable formula depending on units you are familiar with.

| q L gasflow for learn [Pa m 3/s] p SFS sensor full scale pressure [Pa] C min min. controllable conductance of valve [l/s], (refer to «Technical data»)

| q L gasflow for learn [mbar l/s] p SFS sensor full scale pressure [mbar] C min min. controllable conductance of valve [l/s], (refer to «Technical data»)

| q L gasflow for learn [sccm] p SFS sensor full scale pressure [Torr] C min min. controllable conductance of valve [l/s], (refer to «Technical data»)