P4 settings for chiller.

[Ming_]

Good morning Gents,

Need some help with the settings for Temperature Control.

I needed my P4 to switch on my chiller pump from 26.4 deg C to 25.6 deg C.
- i have set Nominal temperature to 25.6 deg C
- Hysteresis to 1.6 deg C ( my understanding is that you x2 the temperature difference you required, 0.8 x 2 = 1.6)
- switch channels functions to Temperature probe, and to cooler.

Doesn't seems to be working, am I missing out any settings?

Thank you!

 

[ingchr1]

With your settings, I believe the Chiller Pump should turn on and off at ~ 26.9C.

From the Programming Guide:

 

[Ming_]

Thank for the quick reply!

Been a long time since i use algebra ..
I will try setting the hysteresis to 0.96 instead.

 

[Ming_]

Need some help again..

Settings as follows:
Aim is for P4 to switch on my chiller pump from 26.4 deg C to 25.6 deg C.
- i have set Nominal temperature to 25.6 deg C
- Hysteresis to 0.96 deg C
- cooling difference is 0 deg C

Currently, the switch turns on at 26.4 deg C, switches off at 26.1 deg C

All help is appreciated!

 

[Ming_]

Our should i be setting the cooling difference at 0.8 deg C, Hysteresis at 0 deg C instead?

 

[ingchr1]

The operation you observed seams correct. The Cooling is turning off when it gets back into the hysteresis band of 1/2*hysteresis.

You can test with the hysteresis set to zero and observe the operation, but I'm thinking you will get excessive cycling. Are you using Temperature 1 for other switch outlets, heaters? If so, keep those in mind.

 

[Ming_]

The operation you observed seams correct. The Cooling is turning off when it gets back into the hysteresis band of 1/2*hysteresis.

You can test with the hysteresis set to zero and observe the operation, but I'm thinking you will get excessive cycling. Are you using Temperature 1 for other switch outlets, heaters? If so, keep those in mind.

Thanks for the quick reply.

Shouldn't the cooling be turn off only when the temperature hit my Nominal temperature of 25.6 deg C ?

Nope, only 1 function is set for Temperature 1
And yes, too many start stops for the chiller with this 0.3-0.4 deg temperature change.

 

[Lasse]

Something fishy here - how is your chillers internal nominal value and hysteresis set? The internal nominal value should be set to very low - test 24 C and the hysteresis lower than ± 1 C Or if it is possible - disconnect the internal control

As you have set your P4 controller it in post 4 - the chiller should turn on at around 26.1 (and above) and of at 25.6 - nothing else.

Sincerely Lasse

 

[Ming_]

Thanks for the reply.

I am not sure i understand your question. Switch is the on and off a chiller pump. Settings of the chiller is irrelevant here?

I am testing the following setting:

- Nominal temperature to 25.6 deg C
- Hysteresis to 0.2 deg C (This the minimum we can set, 0 is not possible)
- cooling difference is 0.7 deg C

Hopefully, switch is on at 26.47 deg C, off at 25.6 deg C

 

[Lasse]

I am not sure i understand your question. Switch is the on and off a chiller pump. Settings of the chiller is irrelevant here?

I suppose your chiller have an internal control - they normally have that. Can you please sent a picture or a manual of your chiller. Or a link to the chiller. Your chiller can´t know that you use an external control, hence if it have an internal control - you must either deactivate that or set it to always work in the interval you want to control externally.

Sincerely Lasse

 

[Ming_]

Thanks for your reply!

Chiller is a chinese Hailea chiller. Currently it is set to run at 25 deg C, stop at 24 deg C.

I think chiller settings is not in play here. My plan is for the chiller pump to stop at 25.6 deg, the chiller can continue to cool the water that is left in it heat exchanger to 24 deg.

Reason for doing this is that my chiller is located far from my tank and i am using a 120watt pump to supply water to the chiller. I hope to save some energy bill by not having to run this pump for 24hrs everyday.

 

[Lasse]

Do you mean that you have a pump managed by Profilux and a Chiller managed by an internal controller. When you say it stops at 26.1 degree - is it the pump or the chiller that stops? Is it profilux temperature probe you read or the chillers?. What says your internal chiller temperature/ P4 temp 1 when the pump runs and when it stops? Is there an internal pump in the chiller

Try to get a clue of whats happens because this settings - as I understand you have - should result in a stop of the pump at 25,6 and start around 26.1

And - IMO - If you want to avoid frequent starts and stops, you should also turn off the chiller - otherwise it works against the temperature changes in the heat exchanger, which happen quickly.

Sincerely Lasse

 

[Ming_]

Do you mean that you have a pump managed by Profilux and a Chiller managed by an internal controller. When you say it stops at 26.1 degree - is it the pump or the chiller that stops? Is it profilux temperature probe you read or the chillers?. What says your internal chiller temperature/ P4 temp 1 when the pump runs and when it stops? Is there an internal pump in the chiller

Try to get a clue of whats happens because this settings - as I understand you have - should result in a stop of the pump at 25,6 and start around 26.1

And - IMO - If you want to avoid frequent starts and stops, you should also turn off the chiller - otherwise it works against the temperature changes in the heat exchanger, which happen quickly.

Sincerely Lasse

Hi Lasse,

Yes, chiller pump is managed by Profilux.
Chiller has its own thermostat, independent of Profilux. Currently chiller is set to run from 25 deg C to 24 deg C.
At the current temperature settings for both Profilux and chiller, basically once water starts pumping into the chiller, the chiller will kick in. Chiller will stop around 30 seconds after pump stops. I have also verified that that both temperature readings from chiller and P4 is the same.


All my settings are as per your screenshot, difference is signal setting to 4, which should not be an issue?

I starting running my chiller pump with Profilux around 12pm yesterday, nominal temperature is always set at 25.6 deg C, played around with the hysteresis and coolding difference.
It is funny temperature just would not go down beyond 26.1 deg C.
Temperature recordings are taken every 15 mins.

I cannot think of any other issue. My digital temperature probe is old, kept in storage for 3 yrs, previously used around 2 years.
I have monitored the readings for around 1 week, cross reference with the readings from my newly purchased chiller. Everything matches, so age of probe should not matter?

 

[Lasse]

What´s your FW of P4? Whats happen if you set the nominal value to 24.5 C?

Have you done a restart of the P4 ( a Norwegian reset as we Swedes says - just take away the power for around 30 sec and plug in it again) During all my years - I have sometimes succeeded to "fix" a problem with a P4 that behave strange - it was like something had stuck in the memory.

Change the signal settings to 1 - its basically say how fast the electrode should report a change. I would also change the sample period to 1 minute for a while. In that way you will see if there is any fast dip (or erratic readings). Is there any strong magnetic (or electrician) fields nearby the temperature cable?

If it still a problem - please open a ticket here (guest login) I think that this is a strange behaviour - it should not work this way IMO.

By the way - I always run my sensor signal filtration at 1. Its a lot of electrical and magnetical noise around a modern reef and the signals are weak

Sincerely Lasse

 

[Ming_]

Most probably I have to open a ticket for this.

System FW is 7.36, should be the newest.
And i have done too many "Norwwegian reset"

I have just found out another problem. My P4 has a PLM-PH/Redox - digTemp expansion card on it.
After unplugged T1 and plug to T2, the temperature reading jumped from 26.3 to 27.1 deg C
My conductivity jump from 1.0202 to 1.0208.

Readings went back to the usual after plugging back to T1.

I may have to remove my expansion can and try everything out again.

 

[Lasse]

I would also change the sample period to 1 minute for a while. In that way you will see if there is any fast dip (or erratic readings).

I strongly recommend this - it means that you either can confirm fast erratic readings or dismiss it. I have notice now and when that a fast signal level below (or above) a set point can change the state from on to off (and vice versa), It can be so fast and short that you do not see it on the temperature scale. with a short sampling time - you will see how the readings swing. Run it with 1 min sample time during an hour or so.

Sincerely Lasse

 

[ingchr1]

Most probably I have to open a ticket for this.

System FW is 7.36, should be the newest.
And i have done too many "Norwwegian reset"

I have just found out another problem. My P4 has a PLM-PH/Redox - digTemp expansion card on it.
After unplugged T1 and plug to T2, the temperature reading jumped from 26.3 to 27.1 deg C
My conductivity jump from 1.0202 to 1.0208.

Readings went back to the usual after plugging back to T1.

I may have to remove my expansion can and try everything out again.

Not sure if this may be the issue, but is the calibration data the same for T1 and T2?

 

[ingchr1]

What I have observed is that the Chiller function turns on and off at the value given by the equation. I don't have a chiller but use the function to control my fans.

I think you should observe the Chiller outlet turning on and off at ~26.4C. Maybe on at 26.4C and off at 26.3C.

T = 25.6 + (0.83)(0.95) + 0

 

[Ming_]

Not sure if this may be the issue, but is the calibration data the same for T1 and T2?

Yes, calibration data for T1 and T2 is the same. Using the same digital probe.
Not sure what happened.

 

[Ming_]

What I have observed is that the Chiller function turns on and off at the value given by the equation. I don't have a chiller but use the function to control my fans.

I think you should observe the Chiller outlet turning on and off at ~26.4C. Maybe on at 26.4C and off at 26.3C.

T = 25.6 + (0.83)(0.95) + 0

Thanks for the reply.
I think the Nominal temperature may be just a reference setting.

So far, i am not able to cool my tank to my set Nominal temperature...