Unisab II Capacity control

[Desaster]

Hi,

I have replaced a Unisab II becaus the relay board was burned. The Unisab II is working, but i can't read the slide position. With a digital multimeter i can measure the 4-20mA so i think the sensor is ok. I have to calibrate the capactiy to min -40% and max 50%. So the capacity indicator stays at 2%. Is there a setting i can do on the Unisab or is the unit broken?
Type of screw compressor is SAB 128 HF 1999 manufacture year.

Thanks

[Josip]

Hi, Desaster

welcome to RE ...


Hi,

I have replaced a Unisab II becaus the relay board was burned. The Unisab II is working, but i can't read the slide position. With a digital multimeter i can measure the 4-20mA so i think the sensor is ok. I have to calibrate the capactiy to min -40% and max 50%. So the capacity indicator stays at 2%. Is there a setting i can do on the Unisab or is the unit broken?
Type of screw compressor is SAB 128 HF 1999 manufacture year.

Thanks


Do you have manual how to setup UNISAB II ???
... there is described complete procedure how to do it...
it is quite simple procedure...

This measure of mA 4-20 you can read when manually change capacity or...?
Do you have A-meter on your panel to check consumption when
you manually change compressor capacity?


Give us some more details
so we can (maybe) give you better suggestion.


Best regards, Josip

[Desaster]

Hi,

no i don't have a complete manual.
I put a multimeter in middle of the unisab and capacity sensor wires (Fluke 179) and then started the compressor. The measured value goes from 4mA to 20mA. I had removed the sensor and manually rotate to check if the % indicator on the unsiab changed but nothing happened.
No I don't have a A-meter on the panel but checked with a portable A-meter and the A increase when the compressor goes to 100%

Thank you

[Josip]

Hi, Desaster




Hi,

no i don't have a complete manual.
I put a multimeter in middle of the unisab and capacity sensor wires (Fluke 179) and then started the compressor. The measured value goes from 4mA to 20mA. I had removed the sensor and manually rotate to check if the % indicator on the unsiab changed but nothing happened.
No I don't have a A-meter on the panel but checked with a portable A-meter and the A increase when the compressor goes to 100%

Thank you

If I understand you .... you have analog type of capacity indicator ... means dial and magnetic coupling in between, right .... if so ... seems that indicator is broken i.e. electrical part not sending signal (miliamps) to UNISAB II if you can read that with multimeter ... but cannot see capacity in % on UNISAB II display ... you can read 2% all time ....

Not sure how you can calibrate -40% to 50% ... as I remember it is possible only to calibrate sensor from 0%-100% and then manually (or with some input signal) you can run your compressor at 50% ... it is not possible to have negative capacity ... mechanically is not possible to go below 0% ... but maybe I did not understand you well ....

Please send your email address via PM to send you manual for UNISAB II 1.13...


Best regards, Josip

[Desaster]

I make pictures of the sensors tomorrow. The sensor is giving the correct signal to the unsiab, but the unisab doesn't recognize the correct position. I don't know why is accepting -40% but this is the only method to let think the slider is always at 2%. So if the machine is running in automatic the unisab is continuing open the valve and the compressor goes 100%. Is this because i have to program the unisab in a different way or some settings are wrong?

Edit: i can't send PM.

Thanks

[Josip]

Hi Desaster,


I sent you manuals for compressor and for UNISAB II ver 1.13 ....

unfortunately ;) you have to read them both and find out how to setup capacity control ....

but, if you need some help please do not hesitate to ask ...
hope someone here RE forums can help you ...



... many years ago I had trouble with the same indicator and UNISAB II in Greece ...
one indicator repaired, but another one had to be replaced with the new one ...
also UNISAB II had to be replaced ...


Best regards, Josip

[Desaster]

Hi,

The A-meter is on the unisab itself. Here some foto and a video showing the calibration settings and the A meter.
This is a video to show you the A-meter and the % indicator of the unisab while running in manual mode.
https://youtu.be/LRyF2LVEyyc

This unisab is a "new" one from another unit and I don't now if worked the capacity indicator. I changed the sensor with a non genuine one and the result are the same. So the problem must be the unisab or some settings.


Can i PM you on Skype? The board private messaging is disabled.

Thank you

[Josip]

He, Desaster


Hi,

The A-meter is on the unisab itself. Here some foto and a video showing the calibration settings and the A meter.
This is a video to show you the A-meter and the % indicator of the unisab while running in manual mode.
https://youtu.be/LRyF2LVEyyc

This unisab is a "new" one from another unit and I don't now if worked the capacity indicator. I changed the sensor with a non genuine one and the result are the same. So the problem must be the unisab or some settings.


Can i PM you on Skype? The board private messaging is disabled.

Thank you

It is ok if you have transformer to read motor current on UNISAB II and it shows that capacity is going up and down ....

Long time ago I was "playing" with all what you are doing now and cannot remember complete procedure ... I must read manual to be sure how to do each step in calibration but cannot be helpful on distance ... sorry ...

but you can (I believe) check all manually ... dismantle positioner only outer part with dial and hand and rotate by hand and read values on display .... but please check complete wiring to be sure your signal is passing to UNISAB II I will try to find schematic drawings for electrical connection of positioner to UNISAB and send to you ... if you can check this reading by multimeter and not with UNISAB II then must be some problem within UNISAB II ... if you cannot read signal with multimeter then problem is within position unit on positioner itself ... maybe you can instal this positioner to another compressor with good "working" UNISAB II and check readings ...

Sorry if I am not too much helpful ....

It is better to send any info to my email ...

Best regards, Josip

[Desaster]

Hi,

I have already disassembled the sensors and rotate by hand. The valute on my multimeter change. So the sensor are working fine. The sensor is connected on 29 30 31. I have not changed the wiring from old to new board. I don't now how to tell you my email address. PM isn't working.

On the contrary you help me a lot. Thanks for that

[Josip]

Hi,

please check your email where I sent
manuals ...

On the same email address you have here on RE forums ....

Best regards, Josip

[Desaster]

oh sorry :rolleyes: my fault. I read now the manuals and give you feedback.

Thank you

[HVACRsaurus]

Hi,
I’m late to the discussion
Have a look at menu item, Diagnosis-AnalogInputs-Cap (capacity)

Here, the raw value should be showing;
0007 @ 0 milliamps
1606 @ 4 milliamp
4818 @ 12 milliamp
8030 @ 20 milliamp

Section 11.Trouble shooting 6), page 138/218

https://docs.google.com/file/d/0B1FBGnpwNbb0YTY0NGIwMDItYzFkMi00ZjFjLWEzMDMtZGY4MzU5MzY5Y2Yz/view

[Desaster]

Hi,

No problem. The situation is now that im at home due to the corona virus. Please excuse me if I cannot give you any answers in the near future.

Thanks

[NH3LVR]

Stay safe and indoors as much as possible.

[Tycho]

The unisab works in mysterious ways my friend :)

If you do not understand after reading the manual, I would have called a unisab technician

[AKI]

Agree with Tycho

[RANGER1]

Would this thing be 20 years old now?
That is saying something I believe.
Obviously need to try basics first.
This thing may have been made not long after the Sabroe technician.

[Desaster]

What i have read in the manual the calibration is done by adjusting zero and span at page 127. This i have already done and checked whit a digital multimeter. If the settings on page 92/93 are wrong, would it display the wrong percentages on main menu?

I can't call a unisab technician. They are competitor and don't like us ;)

Yeah the plc is from 1995 so more than 20 years. It's rock solid.

If i can't get out of this problem i let run the machine just the way she is. In my opinion, a screw compressor should always run 100%(except with inverter).

[RANGER1]

Is it worth swapping wires around to see if it changes anything?
If you manually turn indicator needle by taking it off end of machine,
does it give any normal readings at any point?
In video amps go up & down, does indicator rotate as well.
Had issue with one of these where magnets were damaged not turning indicator.
Sorry if I have asked for something that you may have mentioned earlier.

From what I understand all is normal except % load readout.

[Desaster]

Hi,

yes for sure i can change some wires around.
No if i turn manually the indicator don't give me any reading on the display. Only on my multimeter i can read a value between 4-20mA. So the indicator is working fine.
When the A goes up and down the indicator rotate. So the problem must on the plc input reading or some calibration settings. I don't know.
The machine is working normally except the % reading.
At the moment Italy has locked down and punishes every not necessary work.

[RANGER1]

Desisted,
The beauty of this machine is that it unloads itself mechanically when turned off.
Most compressors you need to know before starting that fully unloaded.
This situation is probably affected when you have a number of compressors & need to know when fully loaded.
Australia changing by the day at the moment, not in lockdown yet, but imagine very soon.
Good luck

[Desaster]

Hi,

Ok then i will leave the machine as it is.
I hope no other country make the same mistake. The quarantine was to late and now people are dying.
Thank you