70
Set Point
Numeric entry of a process value used as a target for PID control. The default value,
units and display format (number of decimal places) used during data entry are defined
based on the Input channel setting selected.
Gain
When the Gain Form setting is Standard, this unitless value is multiplied by the total
of the proportional, integral, and derivative terms to determine the calculated output
percent.
Proportional Gain
When the Gain Form setting is Parallel, this unitless value is multiplied by the normalized
error (current process value versus set point) to determine the proportional component of
the calculated output percent.
Integral Time
When the Gain Form setting is Standard, this value is divided into the integral of the
normalized error (area under the error curve), then multiplied by the Gain to determine
the integral component of the calculated output percent.
Integral Gain
When the Gain Form setting is Parallel, this value is multiplied by the integral of the
normalized error (area under the error curve) to determine the integral component of
the calculated output percent.
Derivative Time
When the Gain Form setting is Standard, this value is multiplied by the change in error
between the current reading and the previous reading, then multiplied by the Gain to
determine the derivative component of the calculated output percent.
Derivative Gain
When the Gain Form setting is Parallel, this value is multiplied by the change in error
between the current reading and the previous reading to determine the derivative com-
ponent of the calculated output percent.
Reset PID Integral
The PID Integral Value is a running total of the accumulated area under the error curve
(Current Integral). When this menu option is selected, this total is set to zero and the
PID algorithm is reset to its initial state.
Minimum Output
Enter the lowest possible pulse rate as a percentage of the Maximum Stroke Rate set
below (normally 0%).
Maximum Output
Enter the highest possible pulse rate as a percentage of the Maximum Stroke Rate set below.
Maximum Rate
Enter the maximum pulse rate that the metering pump is designed to accept (10 – 2400
pulse/minute range).
Input
Select the sensor to be used by this relay
Direction
Set the control direction. This setting is used to determine the sign of the calculated error
(current process value versus set point) and allows flexible control with only positive
values for all PID tuning parameters.
Input Minimum
The low end of the sensor input range, used to normalize errors into percent of full scale
units. These values are set to the nominal range of the selected input sensor by default.
Input Maximum
The high end of the sensor input range, used to normalize errors into percent of full scale
units. These values are set to the nominal range of the selected input sensor by default.
Gain Form
Select the PID Equation Format used to enter tuning parameters.
5.3.11
Relay, Dual Set Point Mode
Output Details
The details for this type of output include the relay on/off state, HOA mode or Interlock status, accumulated on-
time, alarms related to this output, current cycle on time, relay type and the current control mode setting.
Settings
Touch the Settings icon to view or change the settings related to the relay.
Set point
Enter the first sensor process value at which the relay will activate.
Set point 2
Enter the second sensor process value at which the relay will activate.
Deadband
Enter the sensor process value away from the set point at which the relay will deactivate.
