.Buildings.Controls.OBC.ASHRAE.G36.Generic.TrimAndRespond .Buildings.Controls.OBC.ASHRAE.G36.Generic.TrimAndRespondThis block implements the trim and respond logic according to ASHRAE guideline G36, Section 5.1.14.3 and 5.1.14.4.
For each upstream system or plant set point being controlled by a trim and respond loop, define the initial values in system or plant sequences. Values for trim, respond, time step, etc. shall be tuned to provide stable control.
| Variable | Value | Definition |
|---|---|---|
| Device | AHU Supply Fan | Associated device |
| SP0 | iniSet | Initial setpoint |
| SPmin | minSet | Minimum setpoint |
| SPmax | maxSet | Maximum setpoint |
| Td | delTim | Delay timer |
| T | samplePeriod | Time step |
| I | numIgnReq | Number of ignored requests |
| R | numOfReq | Number of requests |
| SPtrim | triAmo | Trim amount |
| SPres | resAmo | Respond amount |
| SPres_max | maxRes | Maximum response per time interval |
The trim and respond logic shall reset setpoint within the range minSet to
maxSet.
When the associated device is off (uDevSta=false), the setpoint
shall be iniSet.
The reset logic shall be active while the associated device is proven
on (uDevSta=true), starting delTim after initial
device start command.
When active, every time step samplePeriod, trim the setpoint by
triAmo.
If there are more than numIgnReq requests, respond by changing
the setpoint by resAmo*(numOfReq-numIgnReq), i.e., the number of
requests minus the number of ignored requests, but no more than maxRes.
In other words, every time step samplePeriod:
triAmo; numOfReq > numIgnReq, also change setpoint by resAmo*(numOfReq
-numIgnReq) but no more than maxRes.
