61
Error Direction
[Under] means that the user wishes to regulate to the set point in an environment where the analyte is being consumed
and as such tends to fall
under
the set point. In this circumstance the control algorithm will attempt to regulate by making
additions of correction feed stock (which contains the analyte) to the controlled volume.
[Over] error direction assumes that the correction applied by the controller will have the effect of diluting or removing
analyte to perform regulation. When [Over] is selected, enter the TPU manually.
Example: In the case of a fermentation where glucose is the controlled analyte the user should select [Under] error
direction since the organisms in the fermentation will consume glucose, thereby forcing the controller to add glucose via
feed stock additions.
Auto-Activation
Auto-Activation automatically starts control once the sample value is within a certain percentage of the setpoint to
minimize over/under correction. Using the default value, control will not start until the monitored sample value is within 5%
of the setpoint. To change this value, touch the Auto-Activation [5.00%] button and enter the new value.
When using Auto-Activation, make sure the monitored sample value is moving towards the setpoint value. If the monitored
sample value is moving further away from the setpoint value, control will need to be started manually.
TPU
Time-Per-Unit error reflects the amount of time that the correction pump must run to correct for an error in concentration
equal to the unit of measure (e.g. g/L, mg/L, etc.).
Touch the [TPU] button. Select [Automatic] to allow the 2960 to calculate the TPU or [Manual] to enter the TPU manually.
If your Error Direction is [Under], calculate the TPU manually.
Automatic TPU Calculation
