MKS PR4000 CONTROLLER driver for labview 8.6

[Blokk]

Ok, thanks for the info 🙂

[Blokk]

deleted, wrote by mistake

[SVP1]

Hi Blokk, I have a problem. It seems that the pr4000 has to open the red light next to setpoint in order to send the setpoint to the MFC. I figured it out by setting the setpoint manually (not Labview).  How can I do this action with the Labview drivers? If I am not understood, it is similar with the output button that you press in a powersupply in order to begin to send the voltage.

[Blokk]

Well, maybe it is possible, but I just activate it manually, by the "ON" button on the front panel of the actual device.

I just let it ON always by the way...it is ON for 1 year now 🙂 And it does not cause any problem...

edit: and setting the flow setpoint to zero will "turn off" the flow naturally. But as always, do not use a MFC as a valve, it has certain leak-rate. Always use a proper hand or automatic valve to totally stop possible flows/leaks...

[SVP1]

Thanks very much for the quick response. It is amazing that it is so simple. I thought that by pressing the ON button would prevent it from entering remote control. 

I have an "ancient" Mass Flow Meter (not Controller) mks 258a attached to a valve (mks 248). So I assume that by setting the setpoint 0, I wont have leak problems. 

[Blokk]

No, if you set it to zero, you will not have considerable flow. But you still have usually a little leak. This can be measured by a helium leak tester if you have one. Also usually manufacturers state the "zero" leak rate of the flow controller. If a little leak is OK, you can live with this. If no leak is allowed, then use a hand valve. Some of our systems require leak tightness of <1E-9 mbar*liter/sec, in this case a MFC is like a "big hole" 😄

edit: http://www.mksinst.com/docs/R/248ABCman.pdf

page 29:

"Maximum Closed Conducatance"

[SVP1]

I see, thank's for the advice. I will close manually the valve of the manometer. 

Now, it remains to achieve the correct voltages for the valve (mks 248) through the setpoint pin 8  of the pr4000. I measured the voltage between pin 8 (setpoint out) and pin 11(ground) and it varies between 200mV to 5.5 V for 0 sccm to 110 sccm accordingly. The problem is that the 248 valve starts to open for >7 V up to 10V for full open.

[Blokk]

Hmm, so you have a (only) Flow Meter (MKS 258a) and a Flow controller (only solenoid, no flow measurement) MKS 248 model?

Is it possible to connect both devices with standard MKS cables to the PR4000 controller, and the controller would measure the flow via the FlowMeter, and according to the setpoint, would send voltage to the Flow Controller solenoid??

edit: I am just reading page 43 in the manual  (http://www.mksinst.com/docs/R/PR4000B-MAN.pdf), but this is not totally clear 🙂 Sorry, I never worked with such separated devices, I only used real MFCs so far (including flow meter AND controller).

edit2: check page 31, it is possible to change the output signal range from 5V to 10V...

But I still do not understand your cabling. How are the two devices are connected to the PR4000?

[SVP1]

Take a look at the image. In the red circle are the two cable sockets of the 248 valve.

Since I didn't know that the setpoint pin (pin 8 at pr4000) wasn't senting the correct voltage for the setpoint number because I didn't press the ON button (hope I don't confuse you), I drove the valve with an external voltage source and figured out its range (about 7<V<10). So, now that I know that the setpoint pin of the pr4000 works as it should, I will check in a couple of days the following: connect the setpoint pin 8 and ground pin 11 to the valve sockets  (instead of the external voltage source) I aspect  to control the flow with the setpoint voltage of the pr4000. I don't see how it is possible to create a loop in which the flow will be compared to the setpoint but I think I will be ok with just setting the setpoint. I will also check the actual flow (via Labview) to see if it equals the setpoint.

Finally, the 258 flow meter is connected to the pr4000 through the 15 pins.

[SVP1]

Hey,  it seems that the pin 8 (setpoint ) can't give the required current for the valve 248a even at 10 V. It remains closed.

I can control the  valve through an SMU which can supply enough power for the valve. The problem is that the sccms are dropping, I suspect because the SMU can't compare the flow signal with the setpoint signal (of course). I know that the 260 controller for that valve works by comparing the actual flow signal with the setpoint and producing an error voltage, so it autocorrects continually the setpoint signal to maintain the specified setpoint.

The question is the following:  Does the pr-4000b work with that principle? Or it acts like an SMU, giving a fixed voltage?

If it autocorrects the setpoint signal continually according to the flow, I may install a voltage amplifier after the pin 8 in order to have the proper power for the valve. (pin 7 = 15V opens the valve)