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CNT-SVX08F-EN

33

PID Control

An alternative way to calculate the proportional and integral gains is by using the following 
calculations:

Proportional gain

0.80

output

 range

throttling range

-----------------------------------------------------

=

Integral gain

0.20

output

 range

throttling range

------------------------------------------------

=

The proportional gain is scaled by a factor of 0.80, so it contributes 80% of the final output. The 
integral gain contributes 20% of the final output.

Example

In a duct static pressure system, an actuator can move the inlet guide vanes of an air handler from 
0–100%, so the output range is 100— a throttling range of 2.0 in. of water column (wc) is desirable. 
A change in pressure of 2.0 in. wc. or more will drive the output from 0–100% or vice versa. The 
calculations look like this:

Proportional gain

0.80 output range

throttling range

-----------------------------------------------------------

0.80 100

2.0 in. wc.

-------------------------------

40

=

=

=

Integral gain

0.20 output range

throttling range

-----------------------------------------------------------

0.20 100

2.0 in. wc.

-------------------------------

10

=

=

=

Therefore, based on the desired throttling range of 2.0 in. wc., the starting proportional gain is 40 
and the starting integral gain is 10.

Duct static pressure

Inlet guide vane or variable frequency 
drive (VFD) position 

0–100%

2.0 in. wc. 

(0.5 kPa)

40.0 (160)

10.0 (40.0)

Discharge air cooling

Electric/pneumatic 

5.0–15.0 psi (34–103 kPa)

20.0°F (11.1°C)

0.4 (4.0)

0.1 (1.0)

Table 7.

Starting gain values for applications

Loop

Output

Throttling 
Range

Proportional 
Gain

Integral

Gain

Summary of Contents for Tracer MP501

Page 1: ...g up and servicing of heating ventilating and air conditioning equipment can be hazardous and requires specific knowledge and training Improperly installed adjusted or altered equipment by an unqualif...

Page 2: ...ult in equipment or property damage only accidents Copyright This document and the information in it are the property of Trane and may not be used or reproduced in whole or in part without written per...

Page 3: ...ink Wiring and Addressing 11 Location Recommendations 12 Operating Environment Requirements 12 Mounting Recommendations 12 Applications for SCC Mode 13 Inputs for SCC Applications 13 BI1 Occupancy or...

Page 4: ...c Applications 24 Binary Output 1 Binary Output 2 24 Binary Output 3 24 AO Analog Output 24 Overriding Outputs 24 Wiring Diagrams 24 Sequence of Operations for Generic Mode 28 Power up Sequence 28 Loo...

Page 5: ...ation and Communication 43 Test Button 43 Manual Output Test 43 Service Pin Button 44 Interpreting LEDs 44 Red Service LED 44 Green Status LED 44 Yellow LonTalk LED 45 Diagnostics 46 Troubleshooting 4...

Page 6: ...Comfort Control profile and controls space temperature to an active setpoint SCC mode supports the following applications Heating control loop Cooling control loop Two pipe heat cool automatic changeo...

Page 7: ...0 in 102 mm Each side 1 0 in 25 mm Top and bottom 4 0 in 102 mm Metal Cover Model Front 24 0 in 610 mm Each side 2 0 in 51 mm Top and bottom 1 0 in 25 mm Figure 1 4 in 102 mm 1 in 25 mm 6 31 in 160 mm...

Page 8: ...CE Emissions EN 50081 1 1992 CISPR 11 Class B EN 61000 3 2 EN 61000 3 3 UL and C UL listed Energy management system UL 94 5V UL flammability rating for plenum use FCC Part 15 Class A Additional Compo...

Page 9: ...enabled if the input is open The loop is disabled if the input is closed A binary switching device such as a flow switch can be used to enable the control loop Binary Output Actuators and Relays There...

Page 10: ...ires in the same wire bundle with any ac power wires Note For application specific wiring information and diagrams refer to the sections Applications for SCC Mode p 13 and Applications for Generic Mod...

Page 11: ...communication link must meet the following requirements All wiring must comply with the National Electrical Code and local codes 22 AWG Level 4 un shielded communications wire recommended for most Com...

Page 12: ...2 F to 122 F 0 C to 50 C Relative humidity 10 90 non condensing Mounting Recommendations Important Leave the cover on when mounting the MP501 to avoid the possibility of damaging the circuit board dur...

Page 13: ...es a signal of 0 Vac with open contacts and 24 Vac with closed contacts The binary input can function in two ways as an occupancy input or as a generic binary input If configured as occupancy the bina...

Page 14: ...output 1 Drive open or stage 1 TRIAC Binary output 2 Drive close or stage 2 TRIAC Binary output 3 Fan relay Analog output AO Controlled actuator 0 10 Vdc Binary Output 1 Binary Output 2 Binary output...

Page 15: ...ulating actuator connected to the controller at the same time Overriding Outputs The MP501 includes a manual output test Use this feature to manually control the outputs in a defined sequence Refer to...

Page 16: ...B A A B ZN GND SET ZONE SENSOR 20 GND AI1 AI BI BI 1 LED COMM5 LED PIN SERVICE BINARY OUTPUTS 1 24V 24V 2 24V 3 GND 24V AC POWER OUT GND AO STATUS LED H Tri state modulating actuator Fan on off Trane...

Page 17: ...BI 1 LED COMM5 LED PIN SERVICE BINARY OUTPUTS 1 24V 24V 2 24V 3 GND 24V AC POWER OUT GND AO STATUS LED H Stage 2 Fan on off Trane zone temperature sensor Not used In LonTalk communication link Out Occ...

Page 18: ...TPUTS 1 24V 24V 2 24V 3 GND 24V AC POWER OUT GND AO STATUS LED H Not used Fan on off Trane zone temperature sensor Not used In LonTalk communication link Out Occupancy or generic input Analog output 0...

Page 19: ...stics have been generated Zone Temperature Control The proportional integral derivative PID control loop in the MP501 calculates the required heating or cooling capacity 0 100 The PID calculation comp...

Page 20: ...ed or communicated setpoint values Occupied Bypass Mode The controller is placed in occupied bypass mode if the controller is operating in the unoccupied mode and either the timed override on button o...

Page 21: ...of the actuator The output defaults to 50 on power up Overdrive logic automatically calibrates the actuator at the fully open and closed positions without continually driving the actuator This can cau...

Page 22: ...he fan cycles regardless of the fan configuration Fan Off Delay After the actuator output has been controlled to its disabled position the MP501 automatically keeps the fan energized for an additional...

Page 23: ...re pressure flow percent ppm SET Not used ZN Not used BI1 Enable Disable or Generic Binary Input The binary input equates a signal of 0 Vac with open contacts and 24 Vac with closed contacts The binar...

Page 24: ...es a larger demand stage 2 binary output 2 will be controlled on Figure 10 p 26 shows a wiring diagram with the MP501 controlling staged outputs Note The MP501 controls only one actuator You cannot ha...

Page 25: ...tor COMM5 B A A B ZN GND SET ZONE SENSOR 20 GND AI1 AI BI BI 1 LED COMM5 LED PIN SERVICE BINARY OUTPUTS 1 24V 24V 2 24V 3 GND 24V AC POWER OUT GND AO STATUS LED H Tri state modulating actuator Interlo...

Page 26: ...puts COMM5 B A A B ZN GND SET ZONE SENSOR 20 GND AI1 AI BI BI 1 LED COMM5 LED PIN SERVICE BINARY OUTPUTS 1 24V 24V 2 24V 3 GND 24V AC POWER OUT GND AO STATUS LED H Stage 2 Interlock device on off Not...

Page 27: ...Vdc actuator COMM5 B A A B ZN GND SET ZONE SENSOR 20 GND AI1 AI BI BI 1 LED COMM5 LED PIN SERVICE BINARY OUTPUTS 1 24V 24V 2 24V 3 GND 24V AC POWER OUT GND AO STATUS LED H Not used Interlock device o...

Page 28: ...communicated the actuator output is overridden to closed and generates a Process Input Failure diagnostic 18 Normal operation begins if no diagnostics have been generated Loop Enable Disable The propo...

Page 29: ...d positions without continually driving the actuator This can cause unnecessary wear Analog The controller takes the PID output of 0 to 100 and scales it for the analog output For example if the analo...

Page 30: ...nd derivative calculations to determine how aggressively to change the output The goal of PID control is to reach the setpoint as quickly as possible without overshooting the setpoint or destabilizing...

Page 31: ...roblem Integral Calculation The integral calculation responds to the length of time the measured value is not at setpoint The longer the measured value is not at setpoint the larger the output of the...

Page 32: ...l use all of its power to bring the error to zero when the error is 2 F 1 1 C or greater Control becomes looser as the throttling range increases Throttling range cannot be programmed directly in a co...

Page 33: ...water column wc is desirable A change in pressure of 2 0 in wc or more will drive the output from 0 100 or vice versa The calculations look like this Proportional gain 0 80 output range throttling ra...

Page 34: ...tic pressure are missed In Figure 16 the sampling frequency is fast enough that the changes in static pressure are tracked accurately Figure 15 Sampling too slowly Sampling points Changes missed by sy...

Page 35: ...if sampling freq is too fast Time Process variable Calculating the Sampling Frequency Table 8 shows suggested program execution frequencies for common applications These are good initial values but i...

Page 36: ...and allow the measured value to stabilize The measured value stabilizes at 70 F 21 C 26 Control the output to the value used in step 3 and record the time it takes to reach the two thirds point determ...

Page 37: ...is 5 seconds PID Loop Action The action of a PID loop determines how it reacts to a change in the process variable such as a room temperature through either Direct action Reverse action Direct Action...

Page 38: ...letely open Reverse Duct static pressure Inlet guide vane position 0 100 Completely open Reverse Duct static pressure Variable frequency drive 0 100 Completely open Reverse Building static pressure Su...

Page 39: ...e error does exceed 2 0 F 1 1 C the PID output can change Figure 21 Error deadband Control Control Setpoint Process variable Error deadband Error As shown in Figure 21 the error deadband is a means of...

Page 40: ...The individual VAV boxes control their valve to the space depending on the supply air temperature If the supply air temperature is relatively warm the VAV box allows more air flow If the supply air t...

Page 41: ...forms Look at the overall situation Can the system do what is expected of it What is happening to the process variable Is it oscillating or failing to reach setpoint Is the output oscillating 43 Check...

Page 42: ...ng frequency of 30 to 60 seconds would work much better in this situation In other words to fix a cycling system slow down the loop Refer to the section Sampling Frequency p 34 Changing the Gains Be c...

Page 43: ...1 controller circuit board LonTalk LED yellow Neuron chip Service Pin button Status LED green Test button Service LED red Neuron ID label Manual Output Test The manual output test sequentially control...

Page 44: ...whether the controller is capable of operating normally refer toTable 13 Table 13 Red Service LED LED Activity Explanation LED is off continuously when power is applied to the controller The controlle...

Page 45: ...munication normal for communicating applications including data sharing LED is on continuously Abnormal condition LED blinks 1 4 second on 1 4 second off for 10 seconds The auto wink option is activat...

Page 46: ...problem that generated the diagnostic is solved Table 16 Diagnostics Diagnostic Probable Cause Consequence Diagnostic type Normal The MP501 has just been powered or a clear alarm command has just been...

Page 47: ...once per second the controller is not executing the application software because the network connections and addressing have been removed Refer to the section Status Indicators for Operation and Commu...

Page 48: ...over service tool and select the MP501 from the Active Group Tree The device plug in for the selected MP501 will appear with the Status screen displayed in the workspace Refer to the Rover Service Sof...

Page 49: ...the initial troubleshooting steps described in Table 17 p 47 and verify general board operation is okay General board problem Step 2 Inspect the wiring Is there a good connection between the wire and...

Page 50: ...the analog output to its disabled position typically 0 The disabled position is set on the PID tab in the Device Configuration screen If the controller is unoccupied but you think it should be in a di...

Page 51: ...uration screen verify that the actuator drive time is not zero The outputs will not drive the actuator if the drive time is 0 Output configuration problem Step 4 At the Device Configuration screen sel...

Page 52: ...put temperature flow pressure percent ppm fails binary outputs 1 and 2 go off The controller will return to normal operation when the sensor is no longer failed Sensor failure diagnostic Step 5 Compar...

Page 53: ...tes adjustable The bypass timer then starts to count down to zero Setting the Occupied Bypass Time to zero disables the timed override function If the controller is unoccupied when someone presses the...

Page 54: ...sed with a communicated occupancy request to place the controller in either occupied mode or occupied standby mode If neither the hardwired binary input nor a communicated request is used to select th...

Page 55: ...ter Zero b Unoccupied Not zero b Bypass a Standby Does not matter Zero b Standby Not zero b Bypass a Not valid Occupied Does not matter b Occupied Unoccupied Zero b Unoccupied Not zero b Bypass a Stan...

Page 56: ...ng 21 Outputs for generic applications 24 analog output 24 binary output 1 binary output 2 24 binary output 3 24 Outputs for SCC applications analog output 15 binary output 3 14 binary outputs 1 and 2...

Page 57: ...ator generic mode 27 Analog 0 10 Vdc actuator SCC mode 17 Staged outputs generic mode 26 Staged outputs SCC mode 17 Tri state modulating actuator generic mode 25 Tri state modulating actuator SCC mode...

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Page 60: ...are committed to using environmentally conscious print practices Trane by Trane Technologies NYSE TT a global climate innovator creates comfortable energy efficient indoor environments for commercial...

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