RODI TDS control with GHL (or Apex)

[CEReefer]

Hi everyone, I just wanted to show some of my work here. This system can tell your controller if it can allow RODI production or not. My RODI system has 2 (for redundancy) motorized ball valves electronically controlled by my Profilux 4, when these are open RODI production starts.

I used:
- a PSC-64D from HM Digital, to measure TDS down to 0.0 ppm (the classic TDS meters go down only to 0), the device puts out a 4-20mA signal.

- then I used an Arduino Uno Rev3, with a 4-20mA signal receiver to decode the signal and set the trigger for one of the Arduino's digital outputs to a specific voltage (1.7V in my case) if the TDS goes above 1.

- The digital signal is then received by a PLM-ADIN card from GHL, if the voltage goes above 1, it won't allow my Profilux 4 controller to open the valves of my RODI filtration system.

If anyone needs help with any of this or the code to make this run, just hit me up.

 

[CEReefer]

Here are the US Solid motorized ball valves (red arrow). The yellow arrow indicates the 1/2" T fitting for the TDS prob of the PSC64-D controller.

 

[jtm235]

Very nice...I am working on a similar project using a Pi and Arduino Mega...to control a lot of stuff including ATO! Just a couple questions:

1) is that motorized ball valve metal? I think RODI water is corrosive to metal.

2) Also, Why not just use a 12v RODI solenoid? They are NC

3) Do you have any other fail safes other than redundant valves?

 

[CEReefer]

Very nice...I am working on a similar project using a Pi and Arduino Mega...to control a lot of stuff including ATO! Just a couple questions:

1) is that motorized ball valve metal? I think RODI water is corrosive to metal.

2) Also, Why not just use a 12v RODI solenoid? They are NC

3) Do you have any other fail safes other than redundant valves?

The motorized ball valves are controlled by my profilux and are stainless steel, they are positioned after the tap and before the filters so they aren’t in contact with RODI. I leave the tap open, and use them to replace the tap, I use 2 for redundancy. You want motorized ball valves as the heat from the solenoid could potentially “burn” the valve (or deteriorate it overtime) and tend to fail a lot.

I have a float valve in the RODI container as an additional redundancy, as well as an high level float sensor that shuts the valves off.

 

[KStatefan]

Not sure how I missed this when you first posted. This is cool.

I am wanting to clean up my setup to eliminate dual level controllers, delay relays mess i have now but it works.

 

[jtm235]

The motorized ball valves are controlled by my profilux and are stainless steel, they are positioned after the tap and before the filters so they aren’t in contact with RODI. I leave the tap open, and use them to replace the tap, I use 2 for redundancy. You want motorized ball valves as the heat from the solenoid could potentially “burn” the valve (or deteriorate it overtime) and tend to fail a lot.

I have a float valve in the RODI container as an additional redundancy, as well as an high level float sensor that shuts the valves off.

Nice, that's a good way to set it up. I am plumbing mine directly to the sump...Definitely with several safeguards in place such as:

- Float valve

- Mechanical water leak detector safety valve:
Amazon product

- Independent AC cutoff leak detector:
Amazon product

- And a digital leak detector built into the controller

This level sensor is used to trigger the ATO:

5 Etape Liquid Level Sensor With Plastic Casing

Multiple Function Sensor Development Tools 5 eTape Liquid Level Sensor with Plastic Casing

www.electromaker.io

Have you considered also running a separate RO flush cycle to mitigate TDS creep? I guess it's a problem depending on the run frequency of your RO/DI system.

 

[niccumec]

Here are the US Solid motorized ball valves (red arrow). The yellow arrow indicates the 1/2" T fitting for the TDS prob of the PSC64-D controller.

I like your use of motorized ball valve versus solenoids due to reliability….

I assume these ball valves cannot be NC (Normally Closed) in event of power failure, correct? Did you consider using one ball valve and one solenoid as your redundancy? Seems like that would add a NC capability to the system.

Which model did you use? 1/2” or 1/4” and how you adapt to the 1/4” RO tubing?

 

[niccumec]

I like your use of motorized ball valve versus solenoids due to reliability….

I assume these ball valves cannot be NC (Normally Closed) in event of power failure, correct? Did you consider using one ball valve and one solenoid as your redundancy? Seems like that would add a NC capability to the system.

Which model did you use? 1/2” or 1/4” and how you adapt to the 1/4” RO tubing?

Ahh, I now see the 1/2” version has NC. Solid 1/2”

 

[n2585722]

I like your use of motorized ball valve versus solenoids due to reliability….

I assume these ball valves cannot be NC (Normally Closed) in event of power failure, correct? Did you consider using one ball valve and one solenoid as your redundancy? Seems like that would add a NC capability to the system.

Which model did you use? 1/2” or 1/4” and how you adapt to the 1/4” RO tubing?

I have been using solenoids for doing this for years now and I have not had any issues but they are normally left off unless the RODI unit is in use. I have one on the input to the RODI unit and two on the output. One is used to refill my DI reservoir and the other to refill my mix tank. I also have one for a flush valve. The 4 solenoids for the RODI are in the top of this photo. The RODI unit is in my garage.

 

[niccumec]

I have been using solenoids for doing this for years now and I have not had any issues but they are normally left off unless the RODI unit is in use. I have one on the input to the RODI unit and two on the output. One is used to refill my DI reservoir and the other to refill my mix tank. I also have one for a flush valve. The 4 solenoids for the RODI are in the top of this photo. The RODI unit is in my garage.

Good to hear on your Solenoid reliability. I have seen lots of posts of failures, which also surprised me as they should only need to be energized while RO is in operation. Perhaps those people have constant start stops due to using a float instead of allowing the RO reservoir to deplete and make larger batches. Larger batches seem better for TDS creep and for not cycling the solenoid as much.

Can’t read the brands you use in the picture. Any preference on solenoid brand / specs?

 

[n2585722]

Good to hear on your Solenoid reliability. I have seen lots of posts of failures, which also surprised me as they should only need to be energized while RO is in operation. Perhaps those people have constant start stops due to using a float instead of allowing the RO reservoir to deplete and make larger batches. Larger batches seem better for TDS creep and for not cycling the solenoid as much.

Can’t read the brands you use in the picture. Any preference on solenoid brand / specs?

Three of my solenoids are U.S. Solid brand. Two are Hydros brand solenoids. The Hydros are the newer ones but are around 3 years now. I got them to try them out and used them on the DI output. One is for DI reservoir refill and the other for mix tank refill. One is not in the photo it is in the RODI unit for a flush valve. I also have one on the DI output that goes to drain if I need to flush that line for any reason like when the DI resin and filters are changed. All are 12v DC solenoids controlled from 12v outputs on my controller.

 

[niccumec]

@CEReefer Thanks for your original post.
I am planning to implement your setup (see below) to better automate my RODI. I think the below will work, but I am not as familiar with the Arduino board / programming to convert TDS signal.
Can you send me the code and board specs you used?
Have you modified your setup since original post?
Feedback on my attached plan?

 

[n2585722]

@CEReefer Thanks for your original post.
I am planning to implement your setup (see below) to better automate my RODI. I think the below will work, but I am not as familiar with the Arduino board / programming to convert TDS signal.
Can you send me the code and board specs you used?
Have you modified your setup since original post?
Feedback on my attached plan?

Hydros has a TDS meter for their controllers that can be used for this. I use my Hydros to control my RODI filter and mixing station. It automatically refills the DI reservoir. It will automatically transfer contents of mixing tank to fresh saltwater reservoir when it goes low and the mix tank is ready to use. The mix tank is then refilled from the RODI filter. All I need to do is add the salt mix and press a button when it is ready for use.

 

[niccumec]

Yeah, I saw that Hydros TDS meter, which looks nice, however, I need to integrate with my GHL control system as that is what controls the booster pump and motorized control valve. I want to avoid mixing control systems.

 

[niccumec]

Of course, that being said, the PSC-64D plus the Arduino may cost as much as a simple dedicated Hydros controller….

 

[n2585722]

Yeah, I saw that Hydros TDS meter, which looks nice, however, I need to integrate with my GHL control system as that is what controls the booster pump and motorized control valve. I want to avoid mixing control systems.

The Hydros RODI Filter type output can control a flush valve and booster pump. I do not have a booster pump but do use the flush valve output. This output controls the flush valve and input solenoid for my RODI. This output is turned on by a combiner output via a relay connected to a sense port. It is setup as a water level input so it can be used on the RODI input. There are two output solenoids on the DI output of the RODI unit. One goes to the DI reservoir and the other to the mix tank. When either one of those outputs turn on it also turns on this input using the combiner output. This output has a maximum on time set to 5 hours and 30 minutes. That is the longest the output will stay on at one time and is a little more than what it takes to fill an empty reservoir. Once that time is reached it will turn on the output and send an alert. I have run past max on time turned off so that will cause it to shut off once the maximum on time has been reached. I also have two outputs setup to prevent both outputs from coming on at the same time. It will fill the first one triggered and the other will have to wait and stay off for the minimum off time before turning on so the maximum on time is reset for the second fill. Also my inputs and outputs that are in the garage are in the last 2 screenshots. My ATO pump is also in the garage but is not displayed on this page. The AWC drain and fill pumps are displayed. When I got my first Hydros controller it went in the garage and I was using my Archon at the tank. I was still able to hand off the RODI control and the ATO and AWC to the Hydros system and had signals going from the Archon to the Hydros and signals from Hydros to the Archon using outputs to drive relays and relay switch contacts to the inputs.

 

[niccumec]

Interesting…. Still getting my head around the Hydros programming/capabilities as I have been using GHL for everything to data.

Am I thinking correctly here:
1. The below stand alone Hydros controls (@ $330) would seem to give me all the controls I would need.
- would use 3 of 4 sense ports
- could program motorized ball valve and booster to turn on vis power strip when level is at LO and turn off at HI
- would have extra safety by setting a max time on for filling RODI tank
- is power strip only WiFI or can it also connect via control cable? Seems like WiFi only could be a vulnerability.

2. Having a totally independent control of mix station could have benefits.
3. I already have ATO/AWC working as I like it with GHL, so no need for a larger controller here.
4. The PSC-64D TDS monitor itself costs ~$275 which is higher than the XS controller + Dual TDS….
5. Your solution would negate the need for programming an Arduino and installing a PLM-ADIN in my GHL controller.

Am I missing something here? Any downsides to this approach?

 

[n2585722]

Interesting…. Still getting my head around the Hydros programming/capabilities as I have been using GHL for everything to data.

Am I thinking correctly here:
1. The below stand alone Hydros controls (@ $330) would seem to give me all the controls I would need.
- would use 3 of 4 sense ports
- could program motorized ball valve and booster to turn on vis power strip when level is at LO and turn off at HI
- would have extra safety by setting a max time on for filling RODI tank
- is power strip only WiFI or can it also connect via control cable? Seems like WiFi only could be a vulnerability.

2. Having a totally independent control of mix station could have benefits.
3. I already have ATO/AWC working as I like it with GHL, so no need for a larger controller here.
4. The PSC-64D TDS monitor itself costs ~$275 which is higher than the XS controller + Dual TDS….
5. Your solution would negate the need for programming an Arduino and installing a PLM-ADIN in my GHL controller.

Am I missing something here? Any downsides to this approach?

The only issue is with the wifi strips they will only change states if they get a command from the controller to do so. So if you loose wifi communications they will stay in whatever state they are in until the power is restored. If this is an issue there is always the XP8 which is a controller with 8 AC outlets. It is connected to the other controllers using a command bus and creating a collective. I would use a backup float valve as a backup regardless of the source of AC. You would need a ASOV valve on the RODI unit to do that but most of them have that valve to shut off the unit when there is no demand. Another good backup would be a leak detector. Hydros has a rope type and a point type leak detector that connects to a sense port. That can be used to turn off the RODI and also send an alert. I have lots of Hydros info on my build thread starting on page 6 starting at post #119 here on R2R. Just click on the My Tank Thread banner in one of my post to get to the thread. I also have several post on the RODI. The first ones were before they had the RODI Filter output type but I was still able to figure out how to get it to refill the reservoirs before the RODI Filter output type was released. I have a DI reservoir, fresh saltwater reservoir and mix tank at my mixing station. So I have three water level sensors in each. One in each is used to display the percentage of full that is still in the container. That is DIY and uses a 0-10v input. There are several that have connected the Apex water level sensors to the 0-10v inputs but that still requires a little DIY. My first Hydros unit was a X4 starter kit. I used the drive ports for ATO and added 2 X2's for more drive ports. Now there is the XD you can get that has just the three drive ports. A drive port is just a 12v DC output and can power 12v devices such as solenoids and small pumps. Hydros has a dosing pump that is connected to drive ports.

 

[niccumec]

Thanks for the detailed response. I will take a look at your build page. At first glance, I think for my purposes, I would need to go with he XP8 to eliminate any WiFi loss issues, but that increases the cost quite a bit. Seems to defeat the “bullletproof” design to eliminate any chance for overfilling RODI tank.

That being said, in the very rare case where WiFi goes out during end of fill, I would still have the manual float HI-HI shut off which should prevent an overflow (which is what many rely on).