# multiplier

I am quite unsure how i can use the arduino to control a high-voltage supply controlling an electro-optic lens. The lens has to have a change in voltage to correct the focus and i want to know if theres a way to get arduino to apply changes in steps with a loop setup?

and i want to know if theres a way to get arduino to apply changes in steps with a loop setup?

There is, as long as your definition of “high voltage” is 0 to 5V.

If not, you might post a link to this mysterious device, over in Project Guidance. You don’t have a Programming question.

Yes, it's possible to use an inverter to generate the high voltage, and control the inverter with the Arduino. What range of voltage is required, and at what current?

dc42:
Yes, it's possible to use an inverter to generate the high voltage, and control the inverter with the Arduino. What range of voltage is required, and at what current?

HV mutiplier goes up to 5kV.

project is to be able to change the voltage supply to a electro-optic lens to focus on images.

would a potentiometer work?

OK, so you already have a "HV multiplier" that can generate 5kV. Can you provide some more information about it, so that we can see whether it could be controlled from an Arduino?

I am trying to control the voltage being applied to the lens.
I have a HV multiplier (emco) and im trying to see if i can use a digital potentiometer or some other equipment that arduino would be able to use to control the output voltage to the lens.

Would it be easier to post a block diagram?

No, what would make it easier would be if you posted a link to the datasheet or other information about the Emco high voltage power supply. Is it one of these http://www.emcohighvoltage.com/proportional-power-supply.php, if so, which exact model?

.

OK, that helps.

1. Is it the 5V input model, or one of the others?

2. Is it being operated close to full load, or nearer to no-load? That affects the maximum input voltage we need to provide.

3. What will be the power supply for the system? (I'm interested in whether we have a couple more volts available than the input to the emco device needs.)

4. To what resolution do you need to set the output voltage?

dc42:
OK, that helps.

1. Is it the 5V input model, or one of the others?

2. Is it being operated close to full load, or nearer to no-load? That affects the maximum input voltage we need to provide.

3. What will be the power supply for the system? (I'm interested in whether we have a couple more volts available than the input to the emco device needs.)

4. To what resolution do you need to set the output voltage?

When you mean 5V input, do you mean voltage supplied from the arduino?

I have a 10kV generator and a normal 10V generator too.

Havent gotten as far as to decide resolution, a competent resolution should be fine to start off i assume.

domo:
When you mean 5V input, do you mean voltage supplied from the arduino?

No, I mean the input to the HV power supply. The Q50 is available in versions for 5V, 12V, 15V and 24V input. Have you chosen a particular model in the series, or is it flexible?

domo:
I have a 10kV generator and a normal 10V generator too.

What I am asking is, what power supply do you intend to use to power the emco? The Arduino’s 5V supply, or maybe some other power supply (such as your 10V power supply) which you may also be using to power the Arduino?

domo:
Havent gotten as far as to decide resolution, a competent resolution should be fine to start off i assume.

The obvious choices are 8 bit resolution (steps of about 20V), 10-bit resolution (steps of about 5V), or 11-bit resolution (steps of about 2.5V). Some associated solutions are:

8-bit: PWM output pin + smoothing RC network + possible op amp + emitter follower. May need to increase the PWM frequency to get the desired response time.

10-bit: 12-bit external DAC + possible op amp + emitter follower.

11-bit: 12-bit external DAC + possible op amp + emitter follower + 12-bit external ADC.

The “possible op amp” would be needed unless you are using the 5V version and it is lightly loaded.

The input is variable, so it can be used via arduino or the external supply. Can you give me an example of an RC network model please? Also, are you referring to the actual setup of the system? Am I to assume that an RC network will be connected to an emitter and operational amplifier?

domo:
Can you give me an example of an RC network model please? Also, are you referring to the actual setup of the system? Am I to assume that an RC network will be connected to an emitter and operational amplifier?

I can't and won't answer that until you answer my earlier question.

dc42:
No, I mean the input to the HV power supply. The Q50 is available in versions for 5V, 12V, 15V and 24V input. Have you chosen a particular model in the series, or is it flexible?

dc42:
What I am asking is, what power supply do you intend to use to power the emco? The Arduino's 5V supply, or maybe some other power supply (such as your 10V power supply) which you may also be using to power the Arduino?

Currently we are running on the Arduino's 5V.
We do have an external power supply that we have not intended to use yet as there were issues with the board being unstable or overheating.

Here is a schematic for a possible solution. Since you still haven’t said, I’ve assumed you are using the 5V version of the Q50 and that 8-bit resolution is sufficient. You will need to increase the PWM frequency if you want the settling time to be lower than a few seconds.

dc42:
Here is a schematic for a possible solution. Since you still haven't said, I've assumed you are using the 5V version of the Q50 and that 8-bit resolution is sufficient. You will need to increase the PWM frequency if you want the settling time to be lower than a few seconds.

It is the 5V input version. Just checked.
8-bit is more than sufficient.

What coding specifically would go into arduino to control this?

Preferably, you should use PID controller software. There is a standard one for the Arduino. What method do you intend to use to select the output voltage? If the device will be standalone, then I suggest a rotary encoder and LCD display.

The 5.6V zener diode in the schematic is intended to limit the voltage fed to the Q50 to 5V. However, the datasheet for the Q50 implies that if you run it with 5V supply when the output is lightly loaded, it will produced more than 5kV, which is outside its safe operating area. Therefore, until you have got the software right (in particular, the PID parameters), I suggest you use a lower voltage zener diode (perhaps 3.9V or 4.7V) in order to limit the supply voltage to the Q50 to a lower value.

Here’s a variation of the circuit that provides better current limiting and avoids the need for a power resistor. You should put a heatsink on the BD435 transistor.

The arduino will recieve data from matlab which measures the focus measure value from the lens. That part of the system has been done.
Depending on the value we need arduino to change the output voltage.

I still am unsure what the transistor does in the diagram.
Also the electro-optic lens needs the +/- ve connection, but on the diagram theres only one coming the hv multiplier.

The transistor passes the power (up to 250mA) to the HV multiplier. The op amp cannot supply enough current by itself.

The high voltage output is on the right hand side of the schematic. The positive side is marked "+ 0-5 kV", and the negative side is marked Gnd. The negative side is common with Arduino ground. If you wanted negative output instead of positive output, then you would need to use model Q50N and change the arrangement of the voltage divider.

dc42:
The transistor passes the power (up to 250mA) to the HV multiplier. The op amp cannot supply enough current by itself.

The high voltage output is on the right hand side of the schematic. The positive side is marked "+ 0-5 kV", and the negative side is marked Gnd. The negative side is common with Arduino ground. If you wanted negative output instead of positive output, then you would need to use model Q50N and change the arrangement of the voltage divider.

Okay my bad, what i meant was that the lense has to electrode probes that would need the voltage going to. Can this just be divided from the output? I dont understand the 9V at the top section either.