RDS 34

[newbfarmer]

Does this mean my RDS controller is pressure based control rather than flow?

Rate control is new to me. Used to just drive at a constant speed on previous machine.

 

[PSQ]

Just to clarify, is it a 34, Delta 34, or Delta 34i? 34 is pretty old, but the fact that it's 3 and 4 means it can do either pressure or flow; 3 was one, 4 was the other, can't remember which way round.
(post a picture of the control box)

If it has a pressure control valve then it can be used for pressure based control (obviously), but if it also has a flow meter (strong chance it doesn't) then it can also be used for flow control, you just choose which method you wish to use in the settings. I've retrofitted a flow meter to pressure based system, so much better than buggering about with pressure based witchcraft.


If it is the Delta34i then here's the manual:

https://d1hu4133i4rt3z.cloudfront.net/attachments/968/968028-e40b7943a764c77a3d5a3336acddb96c.pdf

 

[e3120]

This might sound obtuse, but you can use a pressure controlling valve in a flow based system, as long as you have a flow meter. In fact, I think it's better as, in theory, there's no adjustment for it to make as sections are turned on an off.

I say in theory as pressure and flow are inextricably linked so it's pretty tricky to adjust one without the other. An old fashioned Ramsey valve does a fairly good job of maintaining pressure at variable flow rates.

 

[newbfarmer]

How do I know if I have a flow meter?

 

[newbfarmer]

Just to clarify, is it a 34, Delta 34, or Delta 34i? 34 is pretty old, but the fact that it's 3 and 4 means it can do either pressure or flow; 3 was one, 4 was the other, can't remember which way round.
(post a picture of the control box)

If it has a pressure control valve then it can be used for pressure based control (obviously), but if it also has a flow meter (strong chance it doesn't) then it can also be used for flow control, you just choose which method you wish to use in the settings. I've retrofitted a flow meter to pressure based system, so much better than buggering about with pressure based witchcraft.


If it is the Delta34i then here's the manual:

https://d1hu4133i4rt3z.cloudfront.net/attachments/968/968028-e40b7943a764c77a3d5a3336acddb96c.pdf

It’s a RDS 34. See attached.
Care to explain why pressure based system is so tricky? Thanks.

 

[Andy26]

How do I know if I have a flow meter?

Have you got one of these?

 

[PSQ]

Care to explain why pressure based system is so tricky? Thanks.

With a flow based system you type in the required rate, hit enter, and the controller regulates the flow so that it counts the tank volume correctly down to zero while applying an accurate rate regardless of forward speed.

With a pressure based system, you need to enter the specific gravity of the solution and the nozzle characteristics before you start, and hope that it works out correctly so it uses the right volume.

I have used various RDS flow based systems for the last 27 years before buying a new to me sprayer with a pressure based Delta 34i. It didn’t suit me, so I had a flow meter added and converted it to flow control which just works regardless of specific gravity or nozzle type.