Internet PLC Forum
General => Technical support => Topic started by: MNewmanjr on September 30, 2004, 04:12:44 AM
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I am new at using the T100 PLC and dont want to get off on the wrong foot right off the bat. Can some one tell me how to best hookup a 9amp 12VDC Motor to my plc so that i can run it at two speeds.
I am wanting to run a pump for two chemicals at two different speeds so that my spray nozzles will output at different micron levels. I am planning to use a solenoid after the pump to direct the fluid to either one of two lines mixing the two chemicals after the pump. My DC motor is a 9 amp motor and i presume i will have to use a contactor with it but if i do that how can i control the speed?
Boy, talk about lost...
Any programming help or code would most certainly be helpful as well.
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Hi,
A few days ago burning out some drivers I remember about your posting.(and my motors are require only 5A)
Based on your requirements (9A- and probably the start curent is quite a bit more) my sugestion is to drive the pumps with two diferent voltages - one for each speed.
Use two different outputs from the PLC one for the slow speed and one the the second speed.
You can use a regular relay or solid state relay
dan
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The best way to control the speed of your 12VDC 9.0 Amps motor is to use one of the two PLC PWM (Pulse Width Modulation) outputs. They are usually rated for 10 Amps and can easy be buffered with a Power MOSFET to increase power to load. Then use the PLC PWM command to control the motor speed.
Sincerely;
Albert Martinez
martinezalbert@yahoo.com
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Is 9A the peak current or continous current? Note that the PWM on the T100MD888+ PLC is rated for 10A peak and 2A continous. So if it is a 9A continuous load the output driver will not be able to handle it.
You will need a DC high speed solid state relay that can supply much higher DC current to the motor. The maximum current the solid state relay must be higher than the stalled current (i.e. if the motor is stalled due to friction) in order not to burn out.