NI VeriStand

[JCC_(SK)]

I am very new in VeriStand and I would like to ask you what is the best way to implement simulation of sensors in VeriStand.

I should implement simulation of RTD and Thermocouple Sensors in VeriStand.

Problem with temperature sensors are that Mathematical Equations has high order (RTD is 3rd order (this is not so bad) and Thermocouple is 9th order).

Do I have to implement this Equations on FPGA or VeriStand could calculate them for me in Real-Time engine (and then VeriStand will setup only AO channel level and on FPGA could be implemented only something like reaction/compensation of Excitation Currents from AI)?

What is the common practice to implement Temperature sensors simulation. Sampling/Update rate for Temperature sensors is usually very low.

My configuration is:

• Host PC - developing tools
• PXI controller - NI VeriStand RT Engine
• R Series Multifunction RIO - PXI Card
• NI9151 - R Series Expansion Chassis
• C-series AI & AO  (electrical implementation)

I am looking forward to you answers.

Peter (CLA & CTD)

[joshe]

We are using the 9213 crio module (T/C) and connect is using a Custom Device that NI gave us to do the math.  We had to do some minipulation on the FPGA since the module is slow and we are running at 1KHz.  This was basically putting the T/C in a separate loop and letting the FPGA publish the data at ever cycle even if the T/C data had not updated yet (the FPGA published old data for the T/C to keep up with the Analog Input modules we have).  The Custom Device does the mV to Temperature conversions.

PXI Chassis

9813R FPGA card

Expanson chassis with AI, AO, DI, DO and T/C (9213)

[JCC_(SK)]

Hi Joshe

Thank you for replay.

My Custom Device should do conversion from T to mV (Thermocouple) and Ohms (Thermistor).

I am emulating Thermocouple and Thermistors.

Operator/VeriStand Script will enter Temperature and cRIO module should generate mV and Ohms corresponding to required Temperature.

[JohanS]

Hi,

I just wanted to inform you that we at WireFlow has released a cSeries resistor emulator module (WF3144) for these kind of simulations.

Take a look at www.wireflow.se to see if this can be of interest.

/Johan

[JCC_(SK)]

---

JohanS wrote:

Hi,

I just wanted to inform you that we at WireFlow has released a cSeries resistor emulator module (WF3144) for these kind of simulations.

Take a look at www.wireflow.se to see if this can be of interest.

/Johan

---

Hi JohanS

Thank you for you replay.

It is very interesting.

Maybe next time.

 Peter

[JCC_(SK) · Accepted solution]

Thermocouple (9th order) I implemented on FPGA as Look-Up Table. Look-Up Table initialized by 9th order equation in required range.

RTD (3rd order) implemented directly on FPGA. VeriStand send all parameters every period.