Water pressure sensor 0-5V readings

[Mike]

I have connected a pressure transducer to a measurement unit (Auber Syl-1813). This sensor is a 100 PSI unit with standard measurement values (0.5-4.5V linear voltage output).
Connected to my Auber analyzer (after setting the slope), the result is consistent:
0 bar when not connected and displays 5.2 bar (equivalent to 75 psi) when connected to my water circuit (consistent with an analog pressure gauge).
The voltage measured at this time is 2.6 V.

When I connect the probe to my T3-TB and set a range of 0-5V, I get a value of 10.49 for this pressure.
Shouldn’t my TB unit display a voltage of 2.6 V?

Update : I created a table, assuming that the raw values are psi (because my SYL unit is converting to bars):
0 V means 0 psi
4.5 V means 100 psi
If my pressure is 5.2 bars (equivalent to 75 psi)

I think I have to obtain a value of 75 on my TB unit. But the result is… 124 PSI
Where is my error ?

[maurice]

I am not fully following but it sounds like you putting a certain voltage on the T3 controller and the value you see on the screen does not match what you see on your volt meter on the same signal. Could you verify that you have checked the reading with a volt meter while the sensor is connected to the T3 controller.

Could you show the range setting and voltage reading in T3000 and the corresponding voltage on the volt meter, maybe I can pick something up from that.

[Mike]

Thx Maurice for the fast reply.
The displayed voltage, connected or not connected is the same : 2.6V steady when the pressure is about 5.2 bars

Update::

I did a calibration with another transducer.
Here are the values.

I also redefined some parameters to display bars (instead of psi) and the values I get are consistent between sensors.

My test sensor gave these values:
What can I do with it? A correspondence table? I want to obtain a displayed value of the real pressure.

When I reconnect my “live” sensor, I now get a value of 10.47 in my TB, which broadly corresponds to the measured (analog) pressure of 5.4 bar.
Later, the circuit pressure dropped to 9.86, corresponding to a displayed pressure of 4.9 bars (fluctuating, city water pressure).

Thank you for your comment.

[maurice]

You could use the custom analog input tables, this is exactly what they are for: matching your sensor to the values you want to see.

Custom analog inputs

Here’s some screenshots showing how to configure transducers in general. From the inputs table, click in the range column at Tab1 to bring up the range setting dialog with the various sensor types available and select ‘Custom Range’ 50 at Tab2 which brings up another dialog where you set up the signal table. At Tab4 you see the settings to plug in for a typical 4-20ma or 0-10V transducer at the minimum and maximum range of the sensor. You can also type in the engineering units at Tab5. Finally…

[Mike]

So simple
Thank you Maurice !

Update:
I obtain sometimes (changing but staying in that range) a weird value, even my syl displays the right pressure. Any clue ?

[maurice]

Strange values, I would say increase the filter setting. This will smooth out the readings although it does slow down the respone time. For most HVAC type process readings, these change slowly anyway so a larger filter is fine.

[Mike]

Update

I tested the sensor with a filter: no positive results.

In order to check whether the input port itself is functional, I placed a 10k type 2 probe on it (tested functional separately) and I get no temperature and the status is set to “open” instead of normal.
I tested it with my wiring installed for my pressure transducer but also connected directly to the TB port.

Could the port be faulty? Unfortunately, I no longer have an analog port available on this unit (I’ll be able to temporarily remove a sensor and connect my pressure sensor to this available port).