Do I have to purchase the RD-20148 board to build the reference design ?
No, you can design your own printed circuit board by referring to the schematic in the document. By doing this you can omit any features that you will not require to keep the unit size to a minimum.
I have assembled the reference design on a plug-in breadboard and it is not working. Why ?
Solder-less plug-in breadboards are not a good choice for the Q2SD. The risk of poor connections and susceptibility to electrical noise are high, especially considering the peak requirements of motor drivers. Consider using the RD-20418 PCB.
I have built the RD-20418 reference board and the motor is going the wrong way.
There are a two ways to alter the default motor direction when using the Q2SD. You can either swap the A and B quadrature inputs around or you can bridge the SD link option on the underside of the RD-20418 board. Either of these options will give you the same result.
My motor operates in one direction only. The other direction does not work at all.
The most common issue with this type of problem is no signal to either the A or B quadrature inputs. This will result in the motor operating in one direction only. Please check the connections to the A and B quadrature inputs.
The motor does not move at all when quadrature signal is applied. The motor seems ‘jammed’ and cannot be turned easily by hand.
This indicates that the motor driver and the ENABLE circuitry are working correctly as the motor is being held in position. However there is no valid input signals to the A and B quadrature inputs. If you are using an encoder that is powered from the board ensure that the encoder power input is connected correctly.
The motor does not move at all when quadrature signal is applied. The motor has no power and can be turned easily by hand.
The most likely cause of this type of problem is that the ENABLE term for the motor driver is not active. This could be that the polarity is incorrect or that it is missing. The RD-20418 inverts the ENABLE term, try connecting your ENABLE term directly to the motor driver.
The motor does not always operate when it should. Sometimes it it does not listen to the quadrature inputs.
Both the ENABLE input of the RD-20418 and the ENABLE input of your motor driver require signal levels of a certain magnitude to operate correctly. It is possible that the states of your ENABLE signal do not swing enough .
My motor only works at low speed and seems to ‘jerk’ when turning.
Some motors draw high currents when operating which may cause the power supply to shut down. Check that your power supply is capable of meeting the peak power requirements of the motor and driver.
My motor driver switches off or indicates an error when the motor changes direction.
If your system attempts to change direction too quickly there is a chance that the power required to ‘brake’ and immediately re-start will be too much for either the power supply or the driver (this will also cause mechanical stress). Try to ensure that start and stop conditions do not occur at speed. Make allowances for controlled acceleration and deceleration.
I am using a manual rotary encoder and I have to turn the encoder several times to get the motor to complete one revolution. They are not ‘synchronised’.
The Q2SD will accurately translate the quadrature signals at it’s input to step and direction pulses. The ratio of encoder output to motor rotation is not altered by the Q2SD in any way. You will need to select an appropriate encoder.
If your motor driver has position feedback you could change the motor position encoder.
There is no power coming out of the RD-20418 board but there is power going in.
There is a protection resistor (R8) on the RD-20418 which is to limit the current being drawn from the on-board regulator. Make sure there is nothing plugged into CONN5 and check that it measures 10 ohms. Replace this resistor if necessary.
Resistor R8 on the RD-20418 board is getting hot and is dis-coloured, but everything seems to be working as it should be.
If resistor R8 is getting hot it is likely that you are drawing too much current from CONN5. The total current drawn from CONN5 must not be greater than 150mA.