Hi, I am new to using IC's such as the SN754410NE and ran into an issue while working on a project (which will hopefully be a welding machine once it is done). I have two 12v motors hooked up to the chip, and they run fine forward, but whenever I send a signal to not move at all or to go in reverse they go really slow, the chip heats up a ton, and my power supply shows changing voltage and amperage for some reason. I suspect a short somewhere, but don't understand the chip or electricity well enough to know where it is coming from.
My chip setup is as follows: 5v from arduino mega to power rail on breadboard
ground to ground rail (common ground with rail on other side)
12v DC from power supply to power rail separate from 5v from arduino
ground from power supply hooked to ground from arduino
on the chip, pins 1, 9, and 16 are hooked to 5v power from arduino
pins 4, 5, 12, 13 hooked into common ground
pin 2 on chip hooked into digital pin 2 on arduino
pin 7 on chip to digital pin 3 on arduino
pin 15 on chip to digital pin 7 on arduino
pin 10 on chip to digital pin 8 on arduino
pins 3 and 6 hooked into motor 1 terminals
pins 14 and 11 hooked into motor 2 terminals
pin 8 hooked into 12V DC from power supply
Here is the code I was running:
int lmotF = 2;
int lmotR = 3;
int rmotF = 7;
int rmotR = 8;
void setup() {
// put your setup code here, to run once:
pinMode(lmotF, OUTPUT);
pinMode(rmotF, OUTPUT);
pinMode(lmotR, OUTPUT);
pinMode(rmotR, OUTPUT);
}
void loop() {
// put your main code here, to run repeatedly:
digitalWrite(lmotF, LOW);
digitalWrite(rmotF, LOW);
digitalWrite(lmotR, LOW);
digitalWrite(rmotR, LOW);
delay(25);
}
Standard permanent magnet motors? Please provide motor specs and the actual code you’re using as the code shown will do nothing with all inputs held low.
You need bypass capacitors for proper operation and keep in mind you have no heatsinking for the chip when it is in a breadboard and less than rated current can cause a thermal shutdown. Correct installation requires a pc board with the necessary lands and vias into the ground plane on pins 4/5/12/13. Details are of course in the data sheet.
WattsThat:
Standard permanent magnet motors? Please provide motor specs and the actual code you’re using as the code shown will do nothing with all inputs held low.
You need bypass capacitors for proper operation and keep in mind you have no heatsinking for the chip when it is in a breadboard and less than rated current can cause a thermal shutdown. Correct installation requires a pc board with the necessary lands and vias into the ground plane on pins 4/5/12/13. Details are of course in the data sheet.
To answer the first question, I can't find my motor specs but here is a link to their amazon page:
On the part about the code, I did provide the code I was using. Under the code presented, I was getting some kind of (I presume) shorting, as my power supply was showing C.C. and C.V. lights flashing with changing voltages and amperage draws. Setting the lmotF and rmotF to HIGH makes them go forward without error, but having lmotR or rmotR set to HIGH or everything set to LOW caused problems.
I had seen that data sheet before, and I was under the impression that having those going to the ground with wiring was sufficient, but if it is not, how do I go about wiring it?
Please provide a circuit diagram, hand drawn and photographed is fine. I don't know about anyone else on here, but my brain is wired up to make sense of circuit diagrams, not lists of wires from one place to another. Please don't assume that we all know what is inside a 754410, please show on your diagram what it does, and preferably provide a link to a data sheet.
The code you have provided just sets the 4 pins low then does nothing, I can't imagine how that is supposed to be controlling anything, but then again, maybe with a diagram....
I'm going to take a wild guess based on your description, my wild guess is that you have flyback diodes across your motors, so when current is applied to run forward they are OK, for reverse the diodes short out the motor. I did say 'wild guess'.
That chip contains the diodes needed for back EMF suppression so there is no need to add extra diodes on your motor.
Your description makes no mention of ground connections nor any decoupling capacitors like are shown in the data sheet.
The ground of the power supply must be connected to the ground of the Arduino. But simply it looks like your power supply can’t handle the current and the interference a motor throws out.
What happens when you disconnect the motors and replace then with a resistor and LED. Each motor needs two of these connected in opposite parallel. Then. One LED lights up for one direction of the motor and the other for the motor running in reverse.
Can you please post a copy of your circuit, in CAD or a picture of a hand drawn circuit in jpg, png?
So you can share your solution t anyone who may have a similar problem.
PCGamingKing:
I solved my problem by using two of the LN754410NE chips, one per motor. I don't know why it worked but it did.
Well you are still likely to be putting 10A spikes into a chip with an absolute max rating of 2A, I predict
a short lifetime for those chips due to heavy overload.
