Adding a 2k ohm resistor to drop 24v to 5v question

[mikey553]

Mike, Do you see the Smiley after what I wrote about you all getting confused? That means I am making a joke. To be clear I know I am the one confused. I do appreciate your help and yes I was not clear in what I posted. Sorry. I am a little bit slow on these things. Note, no smiley! That means it is true! Thank you for your help.

Don't worry - we all started from zero knowledge including me. I have read again your posts and would like to make a comment about ALM (alarm) signal. It is not input, but output from the drive. The drive is telling the Acorn board that it is OK (or not). One of my drives has two alarm terminals as well. The output is defined as maximum 30V/100mA. They also say: "The resistance between ALM+ and ALM- is low impedance as default, and will change to high when the drive goes into error protection".

I do not use ALM terminals, but the above phrase tells me that no resistors should be connected to these terminals. If you decide to go to the Centroid forum, show them what you have and ask about alarm connections and possible use of resistors there.

[Black Forest]

Black Forrest, you tried to ask a simple question, but everybody just got confused. Do you know why? You failed to explain yourself, you provided wrong information (you later called the wiring diagram an example) and you are waiting for a good answer. There is no magic here, garbage in - garbage out.

I already told you that I successfully connected a couple of stepper drives and controllers. The principle is the same regardless of the make and model of your hardware. PUL, DIR and ENA inputs are coming to the drive from the controller. Practically every drive I've seen so far is designed to operate on 5V logical inputs. If it is 12V, they recommend adding 1K resistor in series. If it is 24V, they recommend adding 2K resistor in series to limit the current. Usually it is 7-16mA. Every reputable drive manufacturer provides connection diagrams for various types of controllers. You have to look at the Acorn documentation (it is your controller) and determine the voltage of the control outputs it sends to the drives. Then wire the drives accordingly.

I was able to find online manuals for the Leadshine drives (now we know you don't have them) and for the 3HSS2206 drive (you say this is what you have), but not for the Acorn board. Usually ENA signals are of the same voltage as PUL and DIR. Cannot say anything about ALM signals. One of my drive manuals says that if you connect a 5V input signal to a 24V driver terminal, the drive will not work. On the other hand if you connect a 24V signal to a 5V driver terminal, you will damage the drive.

If you are going to post your question on the Centroid forum, at the very least tell them exactly what you have and what you want from them.

Mike, Do you see the Smiley after what I wrote about you all getting confused? That means I am making a joke. To be clear I know I am the one confused. I do appreciate your help and yes I was not clear in what I posted. Sorry. I am a little bit slow on these things. Note, no smiley! That means it is true! Thank you for your help.

[Paul Alciatore]

OK, back on track. If those "inputs that the Alarm and enable connect to" are switches that you can hold on for a few seconds, then an VOM can tell you what the Voltage they provide is.

I did a little searching for the motor controller you showed. I hope that is the actual one you are using. Anyway, I believe it has an internally generated, +5V available on it's terminal boards. IF, and that is a bit "IF", those external controls are just switches, then that +5V from the motor controller would be the way to go. Run it to the switch and the other side of the switch to the + terminal on the input. The - terminal on that input would connect to ground. But do not do this if those external controls provide their own Voltage.

Mikey is correct when he says better information gets better answers. And photos can help. A photo of the connections on that motor controller with the legends clearly legible would be a start. And more on where these control signals are coming from would be great, again with useful photos if possible.

I am sure the Centrod forum can provide some help.

I am sure part of this problem is importers of equipment that do not really understand the customer and his/her problems. They often do not provide even the most rudimentary instructions and that is a shame.

You all get easily confused! The picture of the Acorn board is an example of how my drives get wired to the Acorn. My drives take 5v logic signals. What I am not sure of is are the inputs that the Alarm and enable connect to will be putting 24v out to the motor driver. I think I will have to brave the Centroid forum and ask over there what voltage goes from what to where. Wish me luck.

[FinnoUgric]

They mean a series resistor. The inpout tolerates 5 Volts input or more likely a current generated with the 5 volts. In order to not to fry the circuit with excessive current one has to have a series resistor in there. The resistor can be on either terminal. + or .-. You can also have two resistors in there which are then each connected to their own terminal. In this case the resistor value should be half of the recommended value.
Resistors are not generally very sensitive components so even if You are not that experienced with soldering You might pull it through with ease.
I recommend using axial metal foil resistors with 1 Watt rating. The circuit generates about 0.25 Watts when operating so 0.5 Watt resistor might occasionally get too hot and 0.25 Watt resistor is just too small.

LOL ... I have even made a video about soldering. This one has absolutely NO animations in it 😂

The video is here

Edit: Be very careful to NOT rto connect the terminals the wrong way around. Observe polarity carefully. Since there most likely is an opto isolator, there is also a LED. LED's fry really easily when connected the wrong way around. They tolerate about 5 volts on reverse polarity direction and after that bad things start to happen.

[mikey553]

Black Forrest, you tried to ask a simple question, but everybody just got confused. Do you know why? You failed to explain yourself, you provided wrong information (you later called the wiring diagram an example) and you are waiting for a good answer. There is no magic here, garbage in - garbage out.

I already told you that I successfully connected a couple of stepper drives and controllers. The principle is the same regardless of the make and model of your hardware. PUL, DIR and ENA inputs are coming to the drive from the controller. Practically every drive I've seen so far is designed to operate on 5V logical inputs. If it is 12V, they recommend adding 1K resistor in series. If it is 24V, they recommend adding 2K resistor in series to limit the current. Usually it is 7-16mA. Every reputable drive manufacturer provides connection diagrams for various types of controllers. You have to look at the Acorn documentation (it is your controller) and determine the voltage of the control outputs it sends to the drives. Then wire the drives accordingly.

I was able to find online manuals for the Leadshine drives (now we know you don't have them) and for the 3HSS2206 drive (you say this is what you have), but not for the Acorn board. Usually ENA signals are of the same voltage as PUL and DIR. Cannot say anything about ALM signals. One of my drive manuals says that if you connect a 5V input signal to a 24V driver terminal, the drive will not work. On the other hand if you connect a 24V signal to a 5V driver terminal, you will damage the drive.

If you are going to post your question on the Centroid forum, at the very least tell them exactly what you have and what you want from them.

[MaxHeadRoom]

As I previously suggested, on whatever drive is being used it is often relatively simple to reverse-engineer the first components encountered on the input to determine what is needed if exceeding the recommended input voltage etc.

[Noitoen]

The drive inputs are optically insulated so, all you need is to regulate the current to the leds. 2k might be a bit high so I would go for 1500 ohm which by itself, not counting the resistor already in the circuit will limit to 16ma.

One for each control input

[Black Forest]

You all get easily confused! The picture of the Acorn board is an example of how my drives get wired to the Acorn. My drives take 5v logic signals. What I am not sure of is are the inputs that the Alarm and enable connect to will be putting 24v out to the motor driver. I think I will have to brave the Centroid forum and ask over there what voltage goes from what to where. Wish me luck.

[Paul Alciatore]

Now wait. This is a photo of a motor and motor control box. And you previously posted a wiring diagram of an Acorn CNC controller with three motor controls attached. And the wiring went straight from the Acorn to the motor controls.

The Acorn is very likely only 5 Volts or perhaps a combination of 5 V and 3.3 V. So where does the 24 Volts come into play? Do you have a complete package with the wire harness that connects these components, or are you trying to connect the Acorn to the motor controls yourself. Are you trying to make that wire harness yourself?

Something does not jive here.

This is a picture of my drives and motors.

[Paul Alciatore]

As for attaching a PDF you can take a screen capture by pressing the Print Screen button on any PC and then opening the Paint program and pressing Ctrl-V to paste the screen shot into the window. Then just save it AS a JPG file and that can be posted. The same thing works for almost anything you can get on your computer screen.

As for your connection, your inputs do sound a lot like opto isolated ones. This type of input is frequently used to prevent damage to the computer board. In any case, only one resistor is needed for each input. And you can put it on either the + or the - terminal of that input, IN SERIES.

You can just solder the resistor to one of the leads from the switch and then attach the other side of the resistor to the input, but it is a lot better to mount it in some way or another. If there are connectors that go to these inputs, you may be able to solder the resistor to the connection side of the pin and solder the wire to the resistor with a short piece of heat shrink tubing to cover that solder joint. Then the shell of the connector would cover all that and protect it from harm. Otherwise, a terminal board mounted somewhere and protected by a cover (or inside a small project box) would be the best way to do it. Bring your switch cable to the terminal board and run one wire through the resistor. Then a second cable from the terminal board to the input connection you are working with. You would use three terminals on the terminal board: 1, 2, and 3. The cable from your switch goes to 1 and 2. The resistor from 2 to 3. And the cable to your input from 1 and 3.

A quick calculation tells me that you need a 0.2 Watt resistor. Normal practice is to double the maximum amount of power needed which would be 0.4 Watts in this case, so a 1/2 Watt resistor would be recommended. If it is in open air with at least some clearance on ALL sides you may get away with a 1/4 Watt, but if it is against a circuit board or in an enclosed box or covered with tape or heat shrink tubing, then the 1/2 Watt is definitely the way to go.

I tried to post the manual for the motors and drives but this site won't let me attach a .pdf

The motors and drives a 220v AC closed loop steppers. Sorry for the confusion. The wiring diagram that has the leadshine drives is to show how my drives get the signal wires connected to them. This was the schematic Centroid provided me to show how to wire my drives to the Acorn. Only the signal wires are relevant in that drawing. My drives and motors work fine connected to the Acorn. I just don't have the enable and alarm signal wires connected yet. That is the reason for this post. I suppose I should have posted my question on the Centroid forum but I really really don't like going there. It is much worse than Practical Machinist when asking newbie questions.

[Black Forest]

This is a picture of my drives and motors.

[Black Forest]

Black Forest,
The schematic in post 9 shows, what look to me like, stepper motor drive outputs (A+, A-, B+, B-) while the drawing for the motor in post 16 shows 3 motor connections, U, V, and W, which are usually associated with brushless servo motors. Your schematics don't match.

I tried to post the manual for the motors and drives but this site won't let me attach a .pdf

The motors and drives a 220v AC closed loop steppers. Sorry for the confusion. The wiring diagram that has the leadshine drives is to show how my drives get the signal wires connected to them. This was the schematic Centroid provided me to show how to wire my drives to the Acorn. Only the signal wires are relevant in that drawing. My drives and motors work fine connected to the Acorn. I just don't have the enable and alarm signal wires connected yet. That is the reason for this post. I suppose I should have posted my question on the Centroid forum but I really really don't like going there. It is much worse than Practical Machinist when asking newbie questions.

[genea]

Black Forest,
The schematic in post 9 shows, what look to me like, stepper motor drive outputs (A+, A-, B+, B-) while the drawing for the motor in post 16 shows 3 motor connections, U, V, and W, which are usually associated with brushless servo motors. Your schematics don't match.

[macona]

The inputs will just be optoisolators so all you are doing is adding more resistance to limit the current to the led in the opto. Alarm is an output which tells the controller the drive has faulted. It is the output side of an opto, it does not need a resistor.

[mikey553]

Had a similar experience using an adurino to control steeper motors. Ended up just using a usb charger cube and usb cable.

Arduino with stepper motor drive and motor is next for me. Actually Arduino can be powered via USB port (5 VDC), its power socket (7-12 VDC) or directly to the board. Connecting Arduino to the drive is another story.

Just 2 months ago I did not know anything about Arduino and stepper motors and drives. But an interesting project came up and I have educated myself a little. It's a steep learning curve, but nothing too complicated for a hobby machinist.