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Treadmill controller

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2PAC Mafia

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Hello,

I´m checking a treadmill 180VDC motor controller. The customer told me at start moment he measured 300V so he sent me the MCB to be checked. I´ve been checking the PCB and I can start and stop it from theorical console signals, it works. Then there are signals for UP and DOWN rpm which goes to 2 optocouplers. When a give pulse at optocoupler for UP it switches motor MOSFET and create this signal:

http://www.restoretronic.com/descargas/cintas/1.jpg
http://www.restoretronic.com/descargas/cintas/2.jpg

so as you can see the circuit works from signal from console to last step at Mosfet switching. What I don´t know is the logic behind the console control because in theory when treadmill starts it should do it giving to motor around 30Vdc but the customer measured 300Vdc. If measure with scope the Mosfet output I see as lower point 180Vdc so means maximum motor voltage and if I measure with multimeter it shows 300Vdc. I guess this is because of frequency switching.
I would like to know how can I change speed signal demand input to change PWM input to Mosfet. I see console sends 5Vdc to anode optocoupler diode and catode goes to console also. The serial yellow LED flashes usually so I think console send some kind of frequency pulse.
When I simulate signal I only can get maximum voltage output or 0V output...
 
the customer measured 300Vdc
At which point in the circuit and with what equipment?
At which circuit point were the signals shown measured?
Can you post a link to the schematic?
 
Hi Alec_t,

He measured with a digital multimeter on motor leads.

I measured at PCB output pins, where the motor should be connected.

I haven´t schematic.
 
Presumably the motor has a tacho to feed back speed info to the MCB. Unless you feed pulses from that (or a simulated tacho) won't the MCB simply try to drive the motor at max speed?
 
Yes, there should be always a speed sensor but usually it goes directly to the console who decides to make the signal for speed control. As soon as you start console should send the lower speed signal to the MCB, then if console receives speed signal correctly and the user wants he can change to faster speed. I would say that is the logic behind.

In my case there is a PLD from Lattice at the MCB, that is the brain for all the logic. I have the datasheet but it´s difficult because it´s programmable.

I would like to know which type of signal or logic is sending console to MCB to change speed through the optocouplers.
 
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