Psychrometric Properties of air

We are writing a program to calculate dew point temperature of air for radiant cooling application. Is there a way to know in the program the unit of the temperature selected by customer in the tstat10 screen? Like a special command that returns the unit of an analog input?

A post was split to a new topic: Enthalpy Calculations

There’s no direct way to read the engineering units in a program but there would be a work around using the modbus registers. The programming language has no commands for reading local registers so you would have to read the register from an external controller and feed that back to the local Tstat10 using panel to panel communications. If you have trouble with it I can have someone on the crew write up an example.

Apologies on the wonky work-around. If this is a big feature we could add some commands to simplify things.

Hey Maurice, will really appreciate an example from your team

we did add these parameters in the latest firmware.

745 1 MODBUS_TSTAT10_HUM_DEW_PT 03_06 Read Holding and Write Single 16 Bit Unsigned Integer DEW point of HUM, uint is C
746 1 MODBUS_TSTAT10_HUM_DEW_PT_F 03_06 Read Holding and Write Single 16 Bit Unsigned Integer DEW point of HUM, uint is F
747 1 MODBUS_TSTAT10_HUM_PWS 03_06 Read Holding and Write Single 16 Bit Unsigned Integer HumSensor_Pws
748 1 MODBUS_TSTAT10_HUM_MIX_RADIO 03_06 Read Holding and Write Single 16 Bit Unsigned Integer HumSensor_Mix_Ratio
749 1 MODBUS_TSTAT10_HUM_ENTHALPY 03_06 Read Holding and Write Single 16 Bit Unsigned Integer HumSensor_Enthalpy

Hey Chelsea, thx for the upgrade. How can we get the new firmware?

To update firmware you can connect to the device and navigate to T3000 → help → check for updates → download firmware and update. If you have a lot of devices to update you can use the T3000 → tools → update many.

Chelsea: We need the bacnet equivalent for all these. As dicussed, we want to leave the main VARS table free for applications so you can add them to the large bacnet array along with all the other baud rate, protocol and other settings that would be appropriate.

Todo items: We do need log function working. And this is not an easy one, we need a way to use these items in programs for both bacnet and modbus…

Hey Maurice,

You could use the below formulas for the natural logarithm for values between 0 and 1

Roger Abdo, P.Eng, MBA, LEED GA

Email: roger.abdo@hydrosolar.ca Web: www.hydrosolar.ca

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