Running AFMS Learning Mode

Before Starting Learning Mode

For valid results, first ensure that:

  • The parameters are set correctly. (See Setting AFMS Parameters.)

  • The sensors are calibrated. (See Calibrating the AFMS's Sensors.)

  • The supply air fan is running at a normal, steady rate (without hunting or sporadic spikes).

  • If the unit has a heat recovery wheel, it is turned off.

  • If any heating or cooling sources are located upstream of the MAT sensor, they are turned off.

  • If the unit has a bypass damper, it is set to 100% open.

Checking Learn Ready Status

  1. Go to AFMS , then select the Device Name of the AFMS controller.

  2. Select the Learn tab.

  3. Take note whether Learn Ready reports READY or NOT READY.

Interpreting Learn Ready Status

If READY is reported, you may manually start Learning Mode. (Continue to Manually Starting Learning Mode.)

If NOT READY is reported:

  • Check Sensor Fault. If FAULT is reported, fix any faults found.

    Note: Go to Monitor to find more detailed information on faults. (See Monitoring with an AFMS.)

  • Ensure that Learn Damper Span has completed.

    Note: (Under Configure,) Learn Damper Span must currently be OFF, and Damper Span Learned must report LEARNED.

  • Mixed Air Temp Low Limit Control may be ACTIVE. If that is the case, continue to Enabling Learning Mode to Auto Start.

    Note: Go to Monitor to find Mixed Air Temp Low Limit Control. Go to Configure to find Enable Low Limit and Low Temp Limit. (See Setting AFMS Parameters for important guidance on Low Limit.)

  • Check Min Delta Temp. If the current ΔT (the absolute difference between the outside and return air temperatures) is less than the minimum difference allowed, then continue to Enabling Learning Mode to Auto Start.

    Note: Go to Monitor to find Outside Air Temp and Return Air Temp. Calculate the absolute difference, then compare to Min Delta Temp.

Manually Starting Learning Mode

If Learn Ready reports READY (see Checking Learn Ready Status), you may start Learning Mode manually.

  1. Leave Min Delta Temp set to the default, or adjust it if needed.

    Note: If the ΔT becomes less than the Min Delta Temp, the AFMS controller will abort Learning Mode. This is to insure that the controller does not receive unusable learning samples. Setting the Min Delta Temp at a 15°F or larger difference is recommended.

  2. Leave Time Between Samples (Seconds) set to the default, or adjust it if needed.

    Note: Most often, Time Between Samples (Seconds) can be left on the default (60 seconds). You might increase the value if the damper Stroke Time (see Setting AFMS Parameters) is longer than that of a typical unit, or if the damper actuator requires extra time to respond. You might decrease it if a large ΔT is present and time at the site is limited. However, too little time between samples could result in inaccurate measurements.

  3. For Learning Mode, select ON.

  4. Select Save.

  5. Wait for Learning Mode to complete.

    Note: To calculate the total time (in minutes) that Learning Mode should take to complete, multiply Time Between Samples (Seconds) by 91, then divide by 60.

    Note: Learn Timer shows the elapsed time since Learning Mode started.

Continue to Operating an AFMS.

Enabling Learning Mode to Auto Start

If Learn Ready reports NOT READY because of currently unfavorable temperatures (see Interpreting Learn Ready Status) you may enable the AFMS controller to automatically start Learning Mode when it detects favorable temperatures at a later time.

  1. Leave Min Delta Temp set to the default, or adjust it if needed.

    Note: If the ΔT becomes less than the Min Delta Temp, the AFMS controller will abort Learning Mode. This is to insure that the controller does not receive unusable learning samples. Setting the Min Delta Temp at a 15°F or larger difference is recommended.

  2. Leave Auto Start Delta Temp set to the default, or adjust it if needed.

    Note: When the ΔT reaches the Auto Start Delta Temp, Learning Mode will start. Learning Mode will complete if the ΔT remains greater than the Min Delta Temp for the entire duration. An Auto Start Delta Temp that is at least 20°F more than Min Delta Temp is recommended.

  3. Leave Time Between Samples (Seconds) set to the default, or adjust it if needed.

    Note: Most often, Time Between Samples (Seconds) can be left on the default (60 seconds). You might increase the value if the damper Stroke Time (Seconds) (found under Configure > Damper) is longer than that of a typical unit, or if the damper actuator requires extra time to respond.

  4. For Auto Learn Enable, select ON.

  5. Select Save.

    Note: See the Date of Last Learn and the OAT When Learned once Learning Mode has run automatically.

Continue to Operating an AFMS.

Alternative to Running Learning Mode

While not ideal, the damper characterization data can be calculated and entered manually. This should only be done if — in the allotted time for setting up the AFMS — the ΔT is unlikely to remain greater than the Min Delta Temp for the duration of Learning Mode. See Manually Entering Damper Characterization Data for guidance.