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SMSC EMC2102, User Manual

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Fan Speed Control with the EMC2102 Device

SMSC EMC2102

USER MANUAL

Revision 0.2 (09-17-07)

27

 

5.6.3

Register Change Summary

All register values are default for the tests in this section.

Figure 5.22 Fan Spin and Stall

Fan Drive Setting 

(51h)

Interrupt Status 2 

(23h)

TACH Target (57h)

Stall

TACH Reading (58h)

Summary of Contents for EMC2102

Page 1: ...ns Anomaly sheets are available upon request SMSC products are not designed intended authorized or warranted for use in any life support or other application where product failure could cause or contr...

Page 2: ...5 4 1 General Setup 20 5 4 2 Controlling the Ramp Rate 20 5 4 3 Register Change Summary 22 5 5 Experiment 5 Optimizing RPM Control Response 23 5 5 1 General Setup 23 5 5 2 Fan Configuration Register...

Page 3: ...Fan Speed Control with the EMC2102 Device SMSC EMC2102 USER MANUAL Revision 0 2 09 17 07 3 6 2 8 Using the Tested Parameters 38...

Page 4: ...e 20 Figure 5 16 Default Step Size with Different UPDATE Settings 21 Figure 5 17 Default UPDATE with Different Step Size Settings 21 Figure 5 18 Exceptionally Slow Rate 22 Figure 5 19 Update Time Modi...

Page 5: ...ANUAL Revision 0 2 09 17 07 5 List of Tables Table 5 1 Register Change Summary for Experiment 2 15 Table 5 2 Register Change Summary for Experiment 3 19 Table 5 3 Register Change Summary for Experimen...

Page 6: ...Man software provided by SMSC This user manual also can be used as a reference material for other EMC devices which have fan control features 3 References The following documents should be referenced...

Page 7: ...eed Control with the EMC2102 Device SMSC EMC2102 USER MANUAL Revision 0 2 09 17 07 7 Figure 4 1 EMC2102 Fan Control Evaluation System Figure 4 2 EVB EMC2102 Board USB Cable PC w ChipMan Software EVB E...

Page 8: ...c to the ChipMan application The CMF files may be located anywhere on the hard drive but the XML files MUST reside in the ChipMan directory typically located at C Program Files SMSC ChipMan Chips An X...

Page 9: ...n Abort another pop up window will ask if you want to select an SMSC device Click on Yes and then select the device as shown in Figure 5 3 In the same device selection window the user also has the opt...

Page 10: ...Fan Speed Control with the EMC2102 Device Revision 0 2 09 17 07 USER MANUAL SMSC EMC2102 10 Figure 5 3 Selecting the Device and Master Controller Type Figure 5 4 ChipMan Operation Window...

Page 11: ...mply select File at the top of the window and Import from the pull down menu A pop up window will let the user to locate the right CMF Select the appropriate file and click open The CMF file will then...

Page 12: ...with a legend on top When additional registers with the same data type are selected they are added to the existing plot window In the experiment shown in Figure 5 7 Plot Windows Drive Setting TACH Ta...

Page 13: ...riment 2 is designed to gain familiarity with the closed loop RPM controller implemented in the EMC2102 This experiment will discuss the effects of gain spin up and minimum settings on the closed loop...

Page 14: ...sentative of the response generated Using this basic setup it is possible to explore how well the fan is controlled using default values 5 2 3 Effects of Loading The EMC2102 has the ability to overcom...

Page 15: ...t 2 lists all register value changes from the default cmf load to accomplish the tests Figure 5 10 Effects of Loading Table 5 1 Register Change Summary for Experiment 2 REGISTER NAME ADDRESS DEFAULT V...

Page 16: ...the fan speed fell to below the valid fan speed i e the raw data value in register 58h TACH Reading is greater than the one in register 56h Valid TACH Count since the fan will be considered as stalle...

Page 17: ...s the fan at maximum voltage for of the time set by the SPINUP_TIME 1 0 bits in register 53h The plots in Figure 5 12 Forced Kick Function illustrate this function with a spin up time of 2 0 sec while...

Page 18: ...counts could be displayed on the ChipMan plots Figure 5 13 but will never be used to control the fan because the EMC2102 will not look at the TACH reading until the end of spin up routine 5 3 5 Spin U...

Page 19: ...egister Change Summary for Experiment 3 lists all register value changes from the default cmf load to accomplish the tests Table 5 2 Register Change Summary for Experiment 3 REGISTER NAME ADDRESS DEFA...

Page 20: ...N Configuration register 52h bits 2 0 to determine the time interval between two updates of the controller output and uses the FAN Step register 54h to determine the maximum allowed hexadecimal count...

Page 21: ...0 rpm to 7500 rpm because it gives the fan more power to follow the desired rpm settings In the last experiment an extremely slow ramp rate is demonstrated The UPDATE was set to maximum 1600 ms and th...

Page 22: ...4 lists all register value changes from the default cmf load to accomplish the tests Figure 5 18 Exceptionally Slow Rate Table 5 3 Register Change Summary for Experiment 4 REGISTER NAME ADDRESS DEFAUL...

Page 23: ...meter tells the RPM controller how to interpret the TACH Target register 57h The value of this parameter provides an operating range for the fan by specifying the minimum rpm the 500 rpm setting is fo...

Page 24: ...set the minimum drive to C0h and command an RPM setting of less than 5500 RPM The fan will start at about 5600 rpm 51h C0h Set the target to 6000 rpm and the fan speed follows Drop the fan target spe...

Page 25: ...gister value changes from the default cmf load to accomplish the tests Table 5 4 Register Change Summary for Experiment 7 REGISTER NAME ADDRESS DEFAULT VALUE NEW VALUE COMMENT Fan Configuration 52Bh C...

Page 26: ...the fan In this experiment the Fan Stall and Fan Spin status bits will be checked In order to see the status bits change the Interrupt Status 2 register 23h is plotted along with other registers liste...

Page 27: ...C2102 USER MANUAL Revision 0 2 09 17 07 27 5 6 3 Register Change Summary All register values are default for the tests in this section Figure 5 22 Fan Spin and Stall Fan Drive Setting 51h Interrupt St...

Page 28: ...1 Spin up Lvel RPM Valid RPM Target RPM In this case the spin up level rpm rpm60 or rpm75 is smaller than both valid rpm function of 56h and target rpm function of 57h The theoretical plot of this si...

Page 29: ...start the fan 57h with 6500 rpm The spin up routine will run repeatedly Change the Valid TACH Count 56h to 5800 rpm the problem cannot be fixed since the valid speed is still higher than the fan speed...

Page 30: ...up routine is always higher than the minimum valid speed the EMC2102 will go to the normal operation after the spin up routine Using the EVB EMC2102 to test this situation with rpm75 5650 rpm simply...

Page 31: ...02 should go to the normal operation after the spin up routine However because the large speed difference between the spin up level speed rpm60 or rpm75 and the target speed the closed loop controller...

Page 32: ...solution is to decrease the Fan Step settings which will force the controller to take smaller steps to achieve the target speed When the target speed is too close to the valid speed the problem will...

Page 33: ...loop control will drive the fan up to reach the target therefore the fan speed will never be lower than the valid speed The EMC2102 will go to the normal operation after the spin up routine Using the...

Page 34: ...VB EMC2102 to test this situation with rpm60 4500 rpm simply set the SPINUP_TIME 53h 1 0 250 ms Valid TACH 56h 4400 rpm and start the fan with TACH Target 57h 5500 rpm Multiple spin up routines will b...

Page 35: ...fan is running at a speed of 6000 RPM it will rotate 100 revolutions per second With 2 pulses per revolution the TACH pulse signal frequency will be 200Hz Figure 6 2 Since a higher RPM will yield a hi...

Page 36: ...Man software tool a 5V DC fan s characteristics can be easily tested In general the following parameters need to be characterized Minimum Startup Speed Stall Speed Minimum Valid TACH Speed Maximum Fan...

Page 37: ...ed for the EVB EMC2102 on board DC fan is about 7000 rpm 6 2 4 Determine the Minimum Startup Speed Set the device in Manual Mode 52h 7 0 Write a value for example 80h to Fan Driver Setting register 51...

Page 38: ...ings A minimum of 10 of full fan speed is recommended for margins 6 2 8 1 Spin up LEVEL Register 53h 2 This parameter has to be set so that the corresponding fan speed is greater than Minimum Startup...

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