help with proportional valve 10 to 24v

[gombault]

Hi new to the forum,
I have a problem with a new plc/computer controller i bought for an injection molding machines. The new controller controls the proportional valves using 10v meaning you vary the 10v lower for the different speeds and pressures you want. My machines proportional valves work on 24v, so i need to vary the 24v lower to change my speeds and pressures. I need to rely on the lowering amount of the 10v for a similar lowering on my 24v. The proportional valve coils are 0.5A

 

[Harald Kapp]

A tad unclear, at least to me. Do I understand correctly:

1. the valves require an input control voltage in the range 0 V ... 24 V
2. the controller outputs a control voltage in the range 0 V ... 10 V

In that case you will have to increase the output voltage from the controller by a factor 2.4 from 10 V to 24 V, not lower it.

Is that correct?

Would you be proficient to solder a circuit on your own or do you require an assembled module which needs only correct wiring?

 

[danadak]

So you want to translate 0-10V to 0 - 24V ?

A simple OpAmp circuit can manage that. But you need a power interface to the
OpAmp I gather, and protection for driving inductive load (the valves) ?

This will help calculate basic level translator circuit :

http://www.elektromys.eu/clanky/ele_dacshift/opamp1_output.php?vinmaxsameasvref=on&voutmin=0&voutmax=24&vinmin=0&vinmax=10&vref=&decade=E12

You can buy power opamps but they are a tad pricey. Or design a booster circuit
to handle the power needed.

https://www.ti.com/lit/an/snoa600b/snoa600b.pdf?ts=1747823680394&ref_url=https%253A%252F%252Fwww.google.com%252F

https://www.ampslab.com/RECOMMMENDED%20READ/OPAMP%20BOOSTER/LINEAR%20TECH%20OPAMP%20BOOSTER%20STAGE.pdf

https://www.ampslab.com/RECOMMMENDED%20READ/OPAMP%20BOOSTER/LINEAR%20TECH%20OPAMP%20BOOSTER%20STAGE_2.pdf

What is the resolution needed for the control V ? And accuracy ? Any speed requirements ?

 

[gombault]

The resolution is a bit of a problem to determine. I removed the coil part it is a tiny coil, the plunger is only 9mm in diameter and the total travel of the plunger is only around 10mm, it is spring loaded. The switching speed is what i think you are asking? That don't have to be fast. Most of a injection molding machines functions could work on the same speed and pressure. It's just for when you inject the plastic into the mould, and when you load new plastic you might need to change pressures and speeds for different materials. I think the voltages on the coils will only drop and vary by around 4 to 5 volts in total

 

[Harald Kapp]

My machines proportional valves work on 24v, so i need to vary the 24v lower to change my speeds and pressures.

Let's make sure there is no misunderstanding. From what I can find online typically this type of valve is controlled by a control signal in the range 0 mA... 20 mA or 0 V ... 10 V. This is the control signal only, while the operating voltage of the valve can be 24 V (or any other voltage). The valve then would have separate connections for power (24 V) and control (10 V).
If the valve is driven directly by a proportionally controlled 24 V power supply, then you will need a valve driver between the plc and the valve.
See e.g. this discussion.

 

[ahsrabrifat]

You can buy a Ready-Made Proportional Valve Driver. Look for drivers like Bosch Rexroth VT-VRPA1-537-10/V0/0, Parker PWD00A-400 or Sun Hydraulics DVC series. These accept a 0–10V input and control current or voltage for proportional valves powered by 24V. You wire 24V to the driver, 0–10V to the input, and the valve to the output.
If you decide to switch to a solenoid valve, you can make a driver like this https://www.pcbway.com/project/shareproject/Simple_Solenoid_valve_driver_1340eb55.html