PLUS+1 User Forum

PLUS+1 Hardware => PLUS+1 Compliant Hardware => Topic started by: jashom1 on November 30, 2016, 01:47:02 AM

Title: PVE Control
Post by: jashom1 on November 30, 2016, 01:47:02 AM
Hi Guys,

Has anyone driven PVE(S) coils with a control system that can only source or sink but not both?

Am I correct in assuming that when we use the PVE driver mode on a Danfoss controller it uses a push/pull driver mode for the signal line?

Thanks for your help.

Title: Re: PVE Control
Post by: Marbek_Elektronik on November 30, 2016, 12:47:59 PM
What is exactly your question?

you can connect PVEs to PWM or DigOut.
Title: Re: PVE Control
Post by: Remy on November 30, 2016, 02:19:42 PM
The PVE coils are not controlled by push pull outputs like a pump can do.

For PVEA, PVEH and PVES, the coil required a voltage controlled mode. For instance if you are working at 24V, The power pin of the coil is connected to a sourcing digital out. The signal pin however is expecting a ratiometric signal

Working at 24V, the signal will look like that:

50% (12V)=Neutral
75%(18V)= Full open port B
25%(6V)= Full open port A

So output wise in the Plus1, using PinConfig6 (% of PVE Power), you will control an output varying from 2500 to 7500 in DutyOut. You can use as well Danfoss block to convert a -100%/+100% signal

I encourage you reading the PVE technical infomation

Title: Re: PVE Control
Post by: jashom1 on December 01, 2016, 12:10:38 AM
We are trying to drive the PVES coils with only using a sourcing driver.

The issue that I think we will have is that the PVE pulls the signal line to half the supply voltage when connected.  I have measured 995uA if I place a short to ground and 24V on the signal line, equating to around 24k ohms pull up and pull down resistors on the signal line.  My issue I think we will have is if the controllers driver is unable to pull this signal line lower than the half way mark as it's only a sourcing driver we might have some issues?

We will be proving this today, I just thought I would ask the question if anyone has had these issues before.


Title: Re: PVE Control
Post by: FluidPowerTom on December 01, 2016, 05:40:41 PM
Jashom, the way that you're phrasing what you're trying to do seems very confusing to me, and it sounds like I'm not the only one.  My background is in mechanical engineering, so I may just be missing something.  What exactly do you mean by "a sourcing driver"?  I'd think that you mean a module that is capable of only sourcing voltage or current, and I'm not sure why that would be noteworthy.  Are you trying to say that you only have one sourcing output for both power and signal to the PVES?  If that's the case then simply splice the power source and use a turn pot to control the PVES signal.  It kind of sounds like you're saying that you have one sourcing output and that you're trying to both power the module and regulate current into the signal pin...?
Title: Re: PVE Control
Post by: BRIan on December 01, 2016, 11:04:10 PM
Are you driving it with PLUS+1?
Title: Re: PVE Control
Post by: jashom1 on December 02, 2016, 07:16:23 AM
The PVE is not being driven by Plus1, it's being driven by different controller that only sources a PWM signal (in essence switches to +24V) the signal line of the PVE.

Due to the nature of the PVE that has a pull up and pull down resistor on the signal pin to + supply and - supply to hold it in neutral when the signal wire is disconnected, essentially the module could only drive the PVE in one direction.

My suspicions were true and this is the case.  It has now been solved by using a combination of sourcing and sinking drivers to operate both directions.

Thanks for your help!