Double DC motor control using pulse width modulation

This project is based on the single PWM project. Everything has just been doubled. The circuit diagram is below. The two IRF 630 MOS-FETs are connected to the PWM1 and PWM2 outputs of the Velleman board. The signals from these outputs turns the FETs ON and OFF at a fairly high frequency. As the average ON and OFF time changes, so does the speed of the motor.

Two relays are used to control the direction of the motors. They are connected to the number 8 and 7 digital outputs of the K8055 USB board. The circuit diagram and a suggested PCB layout are below.

The circuit board and motors are shown on the right, connected to the K8055. The motors. Two large red round thingies are connected to the axles to make the things more visible.

The program

To produce a pulse modulated waveform on the K8055, one simply writes to the D to A converter. This produced a voltage at the DAC output and the corresponding waveform at the PWM output. Note that writing 255 produces a minimum and 0 a maximum waveform, so don't be surprised when your motor starts turning the minute the board is connected.

`SYS K8055_OutputAnalogChannel%,1,255`

writes 255 to the DAC channel 1 and this will stop the motor.

`SYS K8055_OutputAnalogChannel%,1,0`

will run a motor at maximum speed. Values in between these extremes will turn the motor with varying speed. Mind you, the resistance of the gears, the load and the type of motor used will also greatly affect the final speed.

As starting and stopping as well as changing direction can cause a possibly harmful back emf, the program stops and starts the motor by ramping the speed up and down one step at a time. The same happens when you change direction. The current speed is always displayed at the bottom of the menu.

Below is a zip archive with the BBC BASIC for Windows program file and the executable of the same program, in case you don't have BB4W

and here is a link to a video of the project

   10 REM K8055_Two-PWM
   20 REM Control two motors using PWM and the Velleman K8055 USB board
   30 REM Version 1.0
   40 REM Jochen Lueg
   50 REM http://roevalley.com
   60 REM February 2012
   70
   80 PROCK8055_init
   90 SYS K8055_CloseDevice%,0
100 SYS K8055_OpenDevice%, 0
110
120 ON ERROR PROCerror
130
140 PROCscreen(380,300)
150 OFF
160 PROCinit
170 SYS K8055_OutputAnalogChannel%,1,255
180 SYS K8055_OutputAnalogChannel%,2,255
190
200 PRINT
210 PRINT " Motor 1"
220 PRINT " Left - Stop - Right . . . . . A - S - D"
230 PRINT " Slower - Faster . . . . . . . K - L"
240 PRINT
250 PRINT " Motor 2"
260 PRINT " Left - Stop - Right . . . . . Z - X - C"
270 PRINT " Slower - Faster . . . . . . . < - >"
280 PRINT
290 PRINT " Leave the program . . . . . . Q"
300
310 REPEAT
320   Key$=INKEY$(0)
330
340   REPEAT UNTIL INKEY(0)=-1
350   IF (Key$="a" OR Key$="A") AND (M1_Direction$="M1_Right" OR M1_State$="M1_Stopped") PROCM1_left
360   IF (Key$="s" OR Key$="S") AND M1_State$="M1_Running" PROCM1_stop
370   IF (Key$="d" OR Key$="D") AND (M1_Direction$="M1_Left" OR M1_State$="M1_Stopped") PROCM1_right
380
390   IF (Key$="z" OR Key$="Z") AND (M2_Direction$="M2_Right" OR M2_State$="M2_Stopped") PROCM2_left
400   IF (Key$="x" OR Key$="X") AND M2_State$="M2_Running" PROCM2_stop
410   IF (Key$="c" OR Key$="C") AND (M2_Direction$="M2_Left" OR M2_State$="M2_Stopped") PROCM2_right
420
430   IF Key$="k" OR Key$="K" THEN
440     M1_RunningSpeed%+=1
450     IF M1_RunningSpeed%>255 M1_RunningSpeed%=255
460     SYS K8055_OutputAnalogChannel%,1,M1_RunningSpeed%
470     M1_StartSpeed%=M1_RunningSpeed%
480     REPEAT UNTIL INKEY(0)=-1
490   ENDIF
500   IF Key$="l" OR Key$="L" THEN
510     M1_RunningSpeed%-=1
520     IF M1_RunningSpeed%<0 M1_RunningSpeed%=0
530     SYS K8055_OutputAnalogChannel%,1,M1_RunningSpeed%
540     M1_StartSpeed%=M1_RunningSpeed%
550     REPEAT UNTIL INKEY(0)=-1
560   ENDIF
570
580   IF Key$="," OR Key$="<" THEN
590     M2_RunningSpeed%+=1
600     IF M2_RunningSpeed%>255 M2_RunningSpeed%=255
610     SYS K8055_OutputAnalogChannel%,2,M2_RunningSpeed%
620     M2_StartSpeed%=M2_RunningSpeed%
630     REPEAT UNTIL INKEY(0)=-1
640   ENDIF
650   IF Key$="." OR Key$=">" THEN
660     M2_RunningSpeed%-=1
670     IF M2_RunningSpeed%<0 M2_RunningSpeed%=0
680     SYS K8055_OutputAnalogChannel%,2,M2_RunningSpeed%
690     M2_StartSpeed%=M2_RunningSpeed%
700     REPEAT UNTIL INKEY(0)=-1
710   ENDIF
720   PROCfeedback(M1_RunningSpeed%,M2_RunningSpeed%)
730
740
750 UNTIL Key$="q" OR Key$="Q"
760
770 PROCM1_stop:PROCM2_stop
780 SYS K8055_ClearAllDigital%
790 SYS K8055_OutputAnalogChannel%,1,255
800 SYS K8055_OutputAnalogChannel%,2,255
810 SYS K8055_CloseDevice%
820 SYS "FreeLibrary",K8055_Board%
830 *QUIT
840 END
850
860
870
880 DEFPROCfeedback(Speed1%,Speed2%)
890 LOCAL S%
900 COLOUR 6
910 S1%=(255-Speed1%)/2.55
920 S2%=(255-Speed2%)/2.55
930
940 PRINTTAB(2,13)M1_State$;"   ";M1_Direction$;"   Speed: ";S1%;"    "
950 PRINTTAB(2,14)M2_State$;"   ";M2_Direction$;"   Speed: ";S2%;"    "
960 ENDPROC
970
980
990 DEFPROCM1_right
1000 PROCM1_stop
1010 SYS K8055_SetDigitalChannel%,8
1020 PROCM1_start
1030 M1_Direction$="M1_Right"
1040 ENDPROC
1050
1060
1070 DEFPROCM1_left
1080 PROCM1_stop
1090 SYS K8055_ClearDigitalChannel%,8
1100 PROCM1_start
1110 M1_Direction$="M1_Left"
1120 ENDPROC
1130
1140
1150 DEFPROCM1_start
1160 FOR J%= 255 TO M1_StartSpeed% STEP-4
1170   SYS K8055_OutputAnalogChannel%,1,J%
1180   PROCfeedback(J%,M2_RunningSpeed%)
1190 NEXT
1200 M1_RunningSpeed%=M1_StartSpeed%
1210 M1_State$="M1_Running"
1220 ENDPROC
1230
1240

1250 DEFPROCM1_stop
1260 FOR J%= M1_RunningSpeed% TO 255 STEP 4
1270   SYS K8055_OutputAnalogChannel%,1,J%
1280   PROCfeedback(J%,M2_RunningSpeed%)
1290 NEXT
1300 M1_State$="M1_Stopped"
1310 M1_RunningSpeed%=255
1320 ENDPROC
1330
1340 DEFPROCM2_start
1350 FOR J%= 255 TO M1_StartSpeed% STEP-4
1360   SYS K8055_OutputAnalogChannel%,2,J%
1370   PROCfeedback(M1_RunningSpeed%,J%)
1380 NEXT
1390 M2_RunningSpeed%=M2_StartSpeed%
1400 M2_State$="M2_Running"
1410 ENDPROC
1420
1430
1440 DEFPROCM2_stop
1450 FOR J%= M2_RunningSpeed% TO 255 STEP 4
1460   SYS K8055_OutputAnalogChannel%,2,J%
1470   PROCfeedback(M2_RunningSpeed%,J%)
1480 NEXT
1490 M2_State$="M2_Stopped"
1500 M2_RunningSpeed%=255
1510 ENDPROC
1520
1530
1540 DEFPROCM1_right
1550 PROCM1_stop
1560 SYS K8055_SetDigitalChannel%,8
1570 PROCM1_start
1580 M1_Direction$="M1_Right"
1590 ENDPROC
1600
1610
1620 DEFPROCM1_left
1630 PROCM1_stop
1640 SYS K8055_ClearDigitalChannel%,8
1650 PROCM1_start
1660 M1_Direction$="M1_Left"
1670 ENDPROC
1680
1690
1700
1710 DEFPROCM2_right
1720 PROCM2_stop
1730 SYS K8055_SetDigitalChannel%,7
1740 PROCM2_start
1750 M2_Direction$="M2_Right"
1760 ENDPROC
1770
1780
1790 DEFPROCM2_left
1800 PROCM2_stop
1810 SYS K8055_ClearDigitalChannel%,7
1820 PROCM2_start
1830 M2_Direction$="M2_Left"
1840 ENDPROC
1850
1860
1870 DEFPROCinit
1880 M1_RunningSpeed%=255
1890 M1_StartSpeed%=100
1900 M2_RunningSpeed%=255
1910 M2_StartSpeed%=100
1920
1930 M1_Direction$="M1_Left"
1940 M1_State$="M1_Stopped"
1950 M2_Direction$="M2_Left"
1960 M2_State$="M2_Stopped"
1970 ENDPROC
1980
1990
2000 DEFPROCscreen(ScreenWidth%,ScreenHeight%)
2010 COLOUR 128
2020 CLS
2030 COLOUR 15
2040 SYS "SetWindowPos",@hwnd%,-1,0,0,ScreenWidth%,ScreenHeight%,0
2050 VDU 26
2060 ENDPROC
2070
2080
2090 DEFPROCerror
2100 PRINT REPORT$;" at line ";ERL :
2110 SYS K8055_ClearAllDigital%,1
2120 SYS K8055_ClearAllAnalog%,1
2130 SYS K8055_CloseDevice%,1
2140 SYS "FreeLibrary",K8055_Board%
2150 END
2160 ENDPROC
2170
2180
2190 DEFPROCK8055_init
2200 REM These are all the system calls in the order found in the manual
2210 SYS"LoadLibrary","K8055D.dll" TO K8055_Board%
2220 SYS"GetProcAddress",K8055_Board%,"OpenDevice" TO K8055_OpenDevice%
2230 SYS"GetProcAddress",K8055_Board%,"CloseDevice" TO K8055_CloseDevice%
2240 SYS"GetProcAddress",K8055_Board%,"ReadAnalogChannel" TO K8055_ReadAnalogChannel%
2250 SYS"GetProcAddress",K8055_Board%,"ReadAllAnalog" TO K8055_ReadAllAnalog%
2260 SYS"GetProcAddress",K8055_Board%,"OutputAnalogChannel" TO K8055_OutputAnalogChannel%
2270 SYS"GetProcAddress",K8055_Board%,"OutputAllAnalog" TO K8055_OutputAllAnalog%
2280 SYS"GetProcAddress",K8055_Board%,"ClearAnalogChannel" TO K8055_ClearAnalogChannel%
2290 SYS"GetProcAddress",K8055_Board%,"ClearAllAnalog" TO K8055_ClearAllAnalog%
2300 SYS"GetProcAddress",K8055_Board%,"SetAnalogChannel" TO K8055_SetAnalogChannel%
2310 SYS"GetProcAddress",K8055_Board%,"SetAllAnalog" TO K8055_SetAllAnalog%
2320 SYS"GetProcAddress",K8055_Board%,"WriteAllDigital" TO K8055_WriteAllDigital%
2330 SYS"GetProcAddress",K8055_Board%,"ClearDigitalChannel" TO K8055_ClearDigitalChannel%
2340 SYS"GetProcAddress",K8055_Board%,"ClearAllDigital" TO K8055_ClearAllDigital%
2350 SYS"GetProcAddress",K8055_Board%,"SetDigitalChannel" TO K8055_SetDigitalChannel%
2360 SYS"GetProcAddress",K8055_Board%,"SetAllDigital" TO K8055_SetAllDigital%
2370 SYS"GetProcAddress",K8055_Board%,"ReadDigitalChannel" TO K8055_ReadDigitalChannel%
2380 SYS"GetProcAddress",K8055_Board%,"ReadAllDigital" TO K8055_ReadAllDigital%
2390 SYS"GetProcAddress",K8055_Board%,"ResetCounter" TO K8055_ResetCounter%
2400 SYS"GetProcAddress",K8055_Board%,"ReadCounter" TO K8055_ReadCounter%
2410 SYS"GetProcAddress",K8055_Board%,"SedtCounterDebouceTime" TO K8055_SetCounterDebounceTime%
2420 ENDPROC

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Back to the Limavady home page

Double DC motor control using pulse width modulation

Two relays are used to control the direction of the motors. They are connected to the number 8 and 7 digital outputs of the K8055 USB board. The circuit diagram and a suggested PCB layout are below.

The circuit board and motors are shown on the right, connected to the K8055. The motors. Two large red round thingies are connected to the axles to make the things more visible.

The program

`SYS K8055_OutputAnalogChannel%,1,255`

writes 255 to the DAC channel 1 and this will stop the motor.

`SYS K8055_OutputAnalogChannel%,1,0`

will run a motor at maximum speed. Values in between these extremes will turn the motor with varying speed. Mind you, the resistance of the gears, the load and the type of motor used will also greatly affect the final speed.

As starting and stopping as well as changing direction can cause a possibly harmful back emf, the program stops and starts the motor by ramping the speed up and down one step at a time. The same happens when you change direction. The current speed is always displayed at the bottom of the menu.

Below is a zip archive with the BBC BASIC for Windows program file and the executable of the same program, in case you don't have BB4W

K8055_Dual-pwm.zip

and here is a link to a video of the project

Video link

Return to the interfacing index

Back to the Limavady home page

Double DC motor control using pulse width modulation

Two relays are used to control the direction of the motors. They are connected to the number 8 and 7 digital outputs of the K8055 USB board. The circuit diagram and a suggested PCB layout are below.

The circuit board and motors are shown on the right, connected to the K8055. The motors. Two large red round thingies are connected to the axles to make the things more visible.

The program

SYS K8055_OutputAnalogChannel%,1,255

writes 255 to the DAC channel 1 and this will stop the motor.

SYS K8055_OutputAnalogChannel%,1,0

will run a motor at maximum speed. Values in between these extremes will turn the motor with varying speed. Mind you, the resistance of the gears, the load and the type of motor used will also greatly affect the final speed.

As starting and stopping as well as changing direction can cause a possibly harmful back emf, the program stops and starts the motor by ramping the speed up and down one step at a time. The same happens when you change direction. The current speed is always displayed at the bottom of the menu.

Below is a zip archive with the BBC BASIC for Windows program file and the executable of the same program, in case you don't have BB4W

K8055_Dual-pwm.zip

and here is a link to a video of the project

Video link

Return to the interfacing index Back to the Limavady home page

`SYS K8055_OutputAnalogChannel%,1,255`

`SYS K8055_OutputAnalogChannel%,1,0`

Return to the interfacing index

Back to the Limavady home page