Trane MUA-SVP01A-EN manual User Configured PID Control, Direct Acting

Functions

User Configured PID Control

This function is applicable to non-recirculating units only. The User Configured PID Control function allows the user to control an analog output based on a user defined analog input and setpoint. See the Typical Wiring and Unit Controller Specification sections of this manual for more information regarding the inputs and outputs. This function also allows the user to select the PID type (direct or reverse acting) and establish upper and lower control limits. Five keypad entries define the operational parameters. These parameters are: User Control Setpoint, Minimum User Setpoint, Maximum User Setpoint, Low Input Value, and High Input Value. The low and high input values describe the input transducer range. The control setpoint is the primary operational parameter while the minimum and maximum setpoints describe the extents of the desired operating range and provide secondary control as described below. The allowable range for all of these parameters is -9999.99 - +99999.99.

The analog input and output are polarity sensitive and can be configured for different types of inputs. See the Typical Wiring and Unit Controller Specification sections of this manual for more information regarding the inputs and outputs.

The analog input must be connected to IN-1. This input must be configured for either of two different types of input signals:

•0-5Vdc: The output impedance must not exceed 10K?. The input impedance of the controller is 1M?. This input is polarity sensitive. Be sure the connections from the source are correctly polarized at the controller.

•Thermistor: Precon type 2 (10k ohm at 77°F) Input voltages should range between 0.489V and 3.825V. See the wiring diagrams for recirculating model units for typical connections of transducers.

•The IN-1 configuration jumpers on the controller must be set for the appropriate input signal.

A contact closure between the appropriate terminals on the unit's terminal strip located in the unit's main control panel will drive the output to 100%. See the Typical Wiring Schematic and Multiplexed Input sections of this manual for more information.

DIRECT ACTING

The controller output is modulated by a PID loop from 0% to 100% based on the User Control setpoint and the input signal. As the input signal increases the output voltage increases. Additionally, a secondary control acts to override the PID loop to scale the output as follows.

If the input variable equals the User Control setpoint, the output will be determined by the PID loop. In this situation the override has no effect on the output value.

If the input variable is above the User Control setpoint, the output could increase from 0% to 100% as the input variable increases from the User Control setpoint

20 Direct-Fired Indoor and Outdoor Units • MUA-SVP01A-EN