Trend Studies - Johnson Controls - Metasys - LIT-12011147 - Software Application - Controller Configuration Tool - 15.0

Controller Tool Help

Brand
Johnson Controls
Metasys
Product name
Controller Configuration Tool
Document type
User Guide
Document number
LIT-12011147
Version
15.0
Revision date
2022-11-18
Language
English

If you are investigating the PID controller's ability to maintain control with either a custom or standard application, you can troubleshoot errors by creating a trend study. A trended item is a data point in the controller that is periodically sampled and logged. Use the Metasys Export Utility to collect the trend data, or simply collect and paste the data into a spreadsheet.

Examine the following parameters when you create your trend study:

  • Controlled Variable (for example, room temperature or discharge static pressure): Trend at intervals equal to the PID Eff Period
  • PID Setpoint: Trend using COV
  • PID Output: Trend at PID Eff Period
  • State of Output Control: Trend using COV

Additional parameters provide details on how the PID is using PRAC+ to adapt tuning parameters. However, investigating these additional parameters requires that you use the FC Bus Engineering View to find the BACnet® Object Identifier (BACoid), and then manually map the objects to include in a trend study. Make sure to trend these parameters:

  • PRAC Status: Trend using COV
  • Eff Proportional Band: Trend using COV
  • Eff Integral Time: Trend using COV