Temperature Sensors

Address pins of TMP100 without slave use.

Manuel001 — Wed, 18 Nov 2009 07:15:13 GMT

Hello!

I have only one TMP100 on a board. How must be connected the ADD0 and ADD1 pins?

Both to GND?

Best regards

Manuel

Temperature sensor-TMP411 - Remote temperature meaurement

Srivatsa Raghunath — Thu, 05 Nov 2009 07:01:54 GMT

We're facing an issue with TMP411 with remote temperature measurement. We've used this to measure the junction temperature of Intel IXP processor. Connection details are shown in attached snaps shot

Observation - TMP ALERT/THERM2 pin is never com up if IXP power is switched OFF

We have to cool down the processor junction temperature well below value the thermal limit set in TMP411 , Alert pin never comes up if we don't power down the IXP. ALERT/THERM2 pin will be return back to high state after the junction temperature reaches below set value. ALERT/THERM2 signal is used to control the ON board power supply , once it low all on board power will be switched OFF , only TMP411 power will alive under this conditions

Pls clarify

TMP275 erroneous values

Tom Scoggins — Mon, 28 Sep 2009 22:06:19 GMT

We have found a case in which we are consistently reading erroneous values from the TMP275 sensor.

At every “sample” our product performs the following sequence (t is time):

1) t=0, power on the TMP275

2) t=44ms, set the converter resolution (R1/R0) to 11-bits

3) t=194ms, read the temperature register

The sequence above occurs once every 3 seconds. In between samples the system is powered down and the voltage slowly decays. In fact, the voltage to the TMP275 is ~0.625V when power is applied at the start of the next sample. If we wait longer between samples (60-seconds), the voltage is much lower and the problem does not occur. Also if we add a 40ms delay before or after step #2 in the sequence above, the problem does not occur at the 3-second update rate.

We are trying to implement a fix or workaround. The 40ms delay seems to work but since I don’t completely understand the problem I don’t feel comfortable in this fix.

Can you help explain why this problem occurs?

external temp sensor for EZ430-RF2480

Brennan — Wed, 11 Feb 2009 08:04:11 GMT

As advised in another thread, I'd like to know what is the best external temperature sensor for the EZ430-RF2480. Its output will be connected to one of the ADC inputs in the target board of the said Zigbee kit. I'd like an option where there will be least additional circuitry involved.

I am currently looking at the TMP421 and TMP441 datasheets. But from the looks of it, the former is closer to my intended application. Any advise from you guys will be greatly appreciated.

TI's AMC6821 thermal sensor for our Telecom Network Processor chip

NARASIMHA BETINI — Wed, 09 Sep 2009 03:03:56 GMT

Hi Rudye,

Thanks for your proactive approach in helping TI user community.

We have decided to use TI's AMC6821 thermal sensor for our Telecom Network Processor chip at RMI.

I am able to write and read the registers in AMC6821. But the local and remote temperature registers always struck at default values.

I enable the config register#4 bit 1 to value 1.

Could you please let me know the procedure and where I am doing wrong. Or is there a special way to read these registers. Imean certain sequence etc.

And also if you have any driver source code for this chip, please sent it across.

Thanks in advance,

Narasimha

nbetini@rmicorp.com

Implement 120 Temperature sensors on a single I2C Bus.

Aseem Gupta — Mon, 19 Oct 2009 12:35:07 GMT

Hi!

I need to implement 120 Temperature sensors on a single I2C Bus. Using MSP430F5438 Microcontroler. How would I do the addressing and if TMP102 ok on such an Implementation.

Thanks

Aseem K Gupta

Introductions

RudyeM — Mon, 17 Nov 2008 23:03:17 GMT

Hi Everyone!

Since the Temperature Sensors community is just beginning, I thought it would be a good time to make introductions. My name is Rudye McGlothlin, and I've been in charge of product marketing for TI's TMP line for about a year and a half. I'll be helping to facilitate the discussion here. My hope for the Temperature Sensors community is that it will become an outstanding resource for utilizing the TMP products to their full potential.

Incidentally, if you would like to put a face with the name, I am featured in this video about our newest digital temperature sensor, the TMP102: http://focus.ti.com/lit/ml/sboc265/sboc265.wmv .

I look forward to meeting everyone and growing this community!

Rudye

TMP102 shut down mode

andy — Thu, 27 Aug 2009 08:48:15 GMT

Hello,

I am using TMP102. Reading a temp value or writing low or high limits is aslo working perfectly. But when I am trying to put this sensor in Shut down mode with One shot/ conversion ready then it stops providing temp value.

Will anyone plz tell me, what is missing in my code?

Here is the code

I2c.Start(SLAVE_ADDRESS);
I2c.putc(0x01); //Write to config. reg
I2c.putc(0xE1); //Value to be written OS = 1 and SD = 1
I2c.Stop();

I am writing this value just on init or do I need to write it again and again.

Thanx

Andy

TMP102 Register Read Prob

Yuvaraj Velumani — Sun, 30 Aug 2009 14:18:11 GMT

Hi,

Iam using TMP102 device in my design. As an initial stage of testing i was trying to read the configuration register default values. Instead of getting 0x60,0xA0 im getting 0x17,0x70 values. I have checked the wavforms in oscilloscope, the data transfer my host master device(OMAP 3530). I am having a 1.8V to 3.3V level translator in between & I measured the waveform at the input of TMP102 only. ADD0 is connecting SDA line & i noted that master is not sending any ACK signal for the last data byte read(data byte 2).

Will it cause any problem.? I tried to write the default values in the cnfiguration register, but in that condition also, iam getting the value as 0x17 & 0x70 only.

Pls hel me in solving this.

Thanks & Regards,

V.Yuvaraj

TMP300 UL comments

EdWalker — Sat, 22 Aug 2009 01:11:39 GMT

TMP300; I am in the middle of an argument with our UL rep that we can’t use a non-UL temperature sensor. However, my position is that the sensor isn’t used as a safety device, merely a temperature shut-down device to keep the product in our optimal operating specs.

Do we have anything that would or could be UL approved?

Signal conditioning circuit applicable to J,K,B,N,R,S and E types of thermocouples.

muzammil siddiqui — Fri, 14 Aug 2009 17:43:13 GMT

Hi all,

If you have the signal conditioning circuit that is applicable to all types of thermocouples , then send me its link. I am making DAQ card which has a 10 bit ADC. The signal conditioning should be perfect enough that the output voltage from

the signal conditioning circuit is in the range of 0 - 5 volts that can be applied to ADC. The input of the signal conditioning

circuit for my application is -10mV to + 80mV. I also read tutorials for signal conditioning of thermocouples, that

also helped me but i want signal conditioning circuit with its explanation.

Waiting for your useful reply

Problems with eZ430-RF2500.

Devora — Fri, 05 Jun 2009 06:06:11 GMT

Hi, i had a eZ430-RF2500 development kit with me. i would like to upgrade the current demo GUI.

i would like to include the RSSI value in the node. currently it show the RSSI ( signal strength in the console. )
i have problems finding where to put that value into the node. is the programm found in the firm ware of the device or in the GUI?

please reply and guide me as soon as possible. as i am doing it as my final year project in singapore.

thanks alot and regrads.

Derek.

Remote Junction Temperature Sensor Connection Basics

Matt — Mon, 02 Feb 2009 21:19:26 GMT

A remote junction temperature sensor (RJS) such as the TMP411 is useful because the device itself does not have to be close to the temperature measurement point of interest. This is important as oftentimes this may be an embedded processor. The RJS interfaces with either a diode or a transistor whose base-emitter voltage is proportional to the junction temperature in question.

To ensure an optimal connection from the remote sensor (i.e. diode or transistor), it is very important to make sure that spike noise from the processor does not couple in to the VBE/VD measurement, otherwise it will create a large temperature measurement error at the output. This can be done by adding some series RC filtering or ferrite beads; however, a best approach always includes a twisted, shielded pair with the shield grounded as close to the TMP411 as possible. The added series resistance will not affect the accuracy of the measurement as RJS devices have a series resistance correction mode that makes them immune to series R up to 3k ohms. Note that simply placing a large capacitor across the inputs (i.e. 1000pF) with no series resistance can actually be a worse approach as the capacitor will act as a sample-and-hold element which will cause a voltage error that will affect the temperature measurement.

Lastly, since RJS devices such as the TMP411 use a 4 current measurement scheme to calculate temperature, this makes the measurement immune to Seebeck (thermocouple) induction at the connection of the RJS to the diode on a processor PCB. If a small amount of mimatched voltage is induced at these solder connections, this will appear as an offset that will subtract out of the temperature calculation peformed by the internal ADC in the TMP411.

--Matt

TMP102 Question

noam — Tue, 13 Jan 2009 10:02:47 GMT