I'm interested in your TPMS FXTH8715027T1 and I have a few questions:

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I'm interested in your TPMS FXTH8715027T1 and I have a few questions:

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jewuanwilliams
Contributor II

I'm interested in your TPMS FXTH8715027T1 and I have a few questions:

1. How precise is the pressure measurement, does it measure to the second or third decimal?

2. Could you provide LCD screen that provides a visual display of measured temperature and pressure?

3. Could you provide a computer/microcontroller that allows me to manipulate the data via addition, subtraction and multiplication of measured pressure and temperature to get a desired output?

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jewuanwilliams
Contributor II

So you all don't sell anything that would allow me to mount the sensor in a tire? I've been working with you all for three months now with hopes of getting the senors, configuring them and installing them in a tire.

To carry out the procedures listed in the AN5136, I would also have to purchase FXTH870xD TPMS Sensor board, correct?


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jasonchiang
NXP Employee
NXP Employee

Do you have problem to purchase FXTH870xD TPMS sensor board ?

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gaurav_kumar1
Contributor I

Very useful chain of conversation here. Currently, I am interested to purchase the evaluation board for 

FXTH870xD TPMS Sensor board . However, am unable to figure out a place from where to buy this? Can you please help ?

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TomasVaverka
NXP TechSupport
NXP TechSupport

Hi Guarav,

We can ship you some evaluation boards depending on your business case, but I would recommend you to create a standard ticket and specify the following:

 

- Brief description of your application, estimated volume and start of production.

- Number of boards, desired pressure (450kPa, 900kPa or 1500kPa) and desired frequency (315MHz or 434MHz).

- Name and address of the person who will receive the boards.

 

Best regards,

Tomas

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jasonchiang
NXP Employee
NXP Employee

Yes, you need to have FXTH870xD TPMS sensor board to carry out the procedures listed in the AN5136. Thanks for understanding.

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jewuanwilliams
Contributor II

My question is how do you install the FXTH87XX sensors in a tire? I thought that it would come installed in a tire valve stem but I only received the 7x7 mm sensor. Do I just place it in the tire? If not, what device do I need to purchase to mount it in a tire?

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jasonchiang
NXP Employee
NXP Employee

       Regarding your question how to install FXTH87xx sensor in a tire, it is designed by TPMS system manufacturing company. AN5136 just provide TX/XR S/W package, you can use it for customization if you design your own TPMS. Most of manufacturing companies are located in Taiwan, for example, Orange, CUB,....

Orange Electronic Co., Ltd. - TPMS(Tire Pressure Monitoring System)

       You can visit their website for reference if you want to purchase their product.

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david_diaz
NXP Employee
NXP Employee

Hello Jewuan,

1. The pressure range of the FXTH8715027T1 device is calibrated (100 - 1500 kPa).

The pressure offset accuracy is +/- 17kPa as follow:

fxth87.jpg

2. You may refer to the following TPMS Display Demo:

http://www.nxp.com/video/tire-pressure-monitoring-sensor-tpms-ipad-display-demo:TPMS-DISPLAY-DEMO

3. The Kinetis KW01 may act as the Receiver for the FXTH870xD TPMS Sensor.

Please refer to the following application note:

http://www.nxp.com/files/32bit/doc/app_note/AN5136.pdf

This application note will first detail KW01 and FXTH870xD register settings, followed by guidance to modify the demonstration software for both parts and to set up a TPMS system using the KW01 connected to a PC as a receiver with a stand-alone FXTH870xD transmitting.

I hope this information will be useful for you.

If I misunderstood your question, feel free to let me know.  I will be glad to help.

Have a great day.

David Diaz.

PS: If my answer helps to solve your question, please mark it as "Correct". Thank you.

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jewuanwilliams
Contributor II

David,

Thanks, your response was very helpful.

Do you have programming code for TPMS display demo you provided?

Is the FXTH8715027T1 sensor compatible with specific tires or will it work with any vehicle tire?

Thanks

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david_diaz
NXP Employee
NXP Employee

Hello Jewuan,

I am glad to know the information was useful for you.

1. In regard with the source code of the TPMS Display Demo, we do not have rights to the source code because it is an application developed by a 3rd party.

You may send me a private message in case you are interested on this demo.

2. TPMS employs pressure sensors installed in valve stems or elsewhere on the wheel rims or in the tire, to provide independent, frequent air pressure measurements for each tire. These measurements are transmitted to the vehicle instrument cluster to inform the driver.

The package should be mounted with the pressure port pointing away from the axis of tire rotation so that centrifugal force will propel any contaminants out of the pressure port. In cases where the application must orient the pressure port pointing inward, care must be taken to assure contaminants do not reach inside the pressure port.

Please be aware that the pressure range of the FXTH8715027T1 is 100-1500 kPa. It support s medium and heavy duty trucks, buses and construction vehicles for TPMS markets.

I hope this information will be useful for you.

If I misunderstood your question, feel free to let me know.  I will be glad to help.

Have a great day.

David Diaz.

PS: If my answer helps to solve your question, please mark it as "Correct". Thank you.

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jewuanwilliams
Contributor II

David,

Thanks again, I'm interested in using the sensor on a truck that doesn't have TPMS installed, will that be a problem? I'm more interested in using the Kinetis KW01 to relay the information from the sensor to a PC.

I really like the demo, but I would want to add another output variable, how difficult would that be?

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jasonchiang
NXP Employee
NXP Employee

AN5136 application note describes FXTH87xx and KW01 behavior.

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jewuanwilliams
Contributor II

Tzyy-Hong

Will the FXTH8715027T1 sensor output the pressure as millivolts? I want to determine to increase in psi from vehicle weight or any additional load and I think the only way to detect small loads like 200 pounds or less, I would need the pressure output in mV which I could use to determine a weight/mV conversion factor given that I know the inflated psi mV output. I hope you understand what I'm asking for, please let me know if I need to be more detailed, the scenario below may help.

Scenario.

- TPMS is installed and tire pressure is measured P1

-The tire is then mounted on a vehicle, taking a portion of the vehicle's load/weight

-The additional load causes the tire pressure to increase to P2

-The sensor recognizes the change to P2 but the change is so small that the receiver does not show it and instead continues to show P1.

This is the case where having the output however small sent to the receiver in the form of millivolts would help in determining weight/psi.

Thanks

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jasonchiang
NXP Employee
NXP Employee

The firmware in FXTH87 family generates a digital value between 1 and 510 counts representing 2.75 kPa per count, between the range 100 to 1500 kPa.  The function described is the same, however instead of attempting to determine a change in millivolts, you would determine a change in kPa.  No need to converter to millivolts, as the sensor provides already the pressure P1 or P2 in kPa.

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amarnathkanchi
Contributor I

Im using 450 kpa chip(part # F874B11XCBNA) and I'm facing an issue in pressure conversion. I filled tyre air of  45 psi and i'm getting pressure value from IC as 0x1FE(Overflow high as per Firmware User guide). Please help.

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jasonchiang
NXP Employee
NXP Employee

      I tried AN5136 sample code running at MRB-019032 orignally. I also load it into FRDM-019032. It works.

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jewuanwilliams
Contributor II

So I received the sensors and receiver, I'm not sure why but I assumed the sensors would come installed inside of a tire valve stem already but its just the sensor. What tire valve stem should I order to put the sensors in?

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jasonchiang
NXP Employee
NXP Employee

        Are you saying that you received FDRM-KW019032 and FXTH87xx EVB ? If, yes. You can find AN5136 S/W package. It is a qick demo setup. You still need to customize it for your product development.

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jasonchiang
NXP Employee
NXP Employee

Hi,

   I am not familiar with FXTH87xx product and I already forward your question to the expert of FXTH87xx product team. I hope that they can give you reply soon. Sorry for inconvenience caused.

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jewuanwilliams
Contributor II

Thanks, can you provide a link for information about the AN5136?

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