UPW 50 results:

Datasheet values:

- typical +/-3 ppm/K (0..85 deg C)

- max. +/-5 ppm/K (-55..125 deg C)

http://www.te.com/commerce/DocumentDelivery/DDEController?Action=showdoc&DocId=Data+Sheet%7F1773299%7FB%7Fpdf%7FEnglish%7FENG_DS_1773299_B_UPW-0312.pdf%7F1624323-6--------------------------------------------------------------------------------------------------------

UPW50 #1 1K 0.1% Datecode 0816 resistor value @25 deg about -100 ppm against Z201#1

First results from 17.06.2014

on 17.06.2014 the 2 NTCs are fixed to the UPW50 on opposite sides (top + bottom) with tape.

The resistor is taped to the heat spreader directly above the NTC which is used for the temperature controller of the heating foils.

The Fan is installed. (But obviously I have used too much tape).

There is a relative large difference between the temperature of the 2 NTCs visible.

see: 20140617_UPW50_Tdiff_NTC2_NTC1.PNG

And the difference is also dependant on temperature slope.

The difference between +0.3K/minute and -0.3K/minute is up to 0.8K between the 2 NTCs.

Whats the real temperature of the resistor then?

It is not possible to tell wether the observed hysteresis of the resistor curve

is really from the resistor or if it is simply a temperature measurement error.

So for hysteresis I will have to improve the measurement setup thermal coupling (see discussion below).

For the T.C. measurement the thermal coupling has less influence,

since I have waiting times at the temperature extremes for temperature settling.

So the final results will not significantly differ from that what I have up to now:

Picture: 20140617_TC_UPW50_1K_1_raw_temp.PNG

For the UPW50 1K sample #1 this is after the box method:

dev (ppm) temp (deg C) min -42.04121928 8.4112 max 32.44987977 44.5383 diff 74.49109905 36.1271 TC = 2.061917482 |

The measured curve is not straight linear with slightly decreasing T.C. at higher temperatures.

So the T.C. after box method is dependant on measured temperature span.

I calculated a 3rd order regression curve after normalisation to 25 deg C.

See picture 20140617_TC_UPW50_1_LMS.PNG

So the A1 coefficient is the linear part of T.C. at 25 degrees.

T.C. Curve = A0 + A1 * t + A2 * t * t + A3 * t * t * t with: t = (Temp - 25 deg)

A 0 = -7.1365771688644140E-0001

A 1 = 2.0716957976478127E+0000

A 2 = -2.2325669247677248E-0002

A 3 = 1.1149432124690903E-0004

max. deviation to regression curve: 1.4751894259493142E+0000

So measured T.C. at 25 degrees is 2.1 ppm / K.

23.06.2014: further results from 20.06.2014:

change in setup: UPW50 mounted between 2 stacked SK09 heat sinks with thermal grease for the UPW50 + 2 NTCs.

NTC1 is between bottom heat sink and UPW50. NTC2 is above UPW50. Some silicone foil between upper and lower heat sink for better thermal contact. Ramp is 0.3 K / minute.

The difference between NTC2 and NTC1 is much smaller between rising and falling temperature.

But no significant effect on UPW50 hysteresis.

further results from 21.06.2014:

same setup as on 20.06.2014 only setpoint ramp changed to 0.12K / minute.

The "hysteresis" did not change significantly.

If there was a thermal settling time I would have expected a factor 2.5 lower hysteresis for UPW50.

But this is not visible in the measurement.

T.C. curve coefficients:

A 0 = 7.5167802876286093E-0001

A 1 = 2.0586430917904010E+0000

A 2 = -2.2608480477597587E-0002

A 3 = 1.6552949180267930E-0004

max. deviation 1.6919232571042099E+0000 ppm

further results from 22.06.2014:

same setup as on 20.06.2014+21.06.2014 only setpoint stepwise starting from 30 degrees (over night) then

3 hours 25 degrees,

2 hours 8.5 degrees (not reached),

3 hours 25 degrees,

2 hours 46 degrees,

4 hours 25 degrees.

still a remaining hysteresis of around 1.3 ppm (zoomed picture)

By the way: NTC1 below UPW50 shows some overshoot on setpoint changes. NTC2 lags somewhat. So the true temperature might be somewhere inbetween.

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measurements of 29.06.2014

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Against 21.06.2014 2 isothermal blocks where used.

UPW50 #1 is mounted in the brass cube 40mm of branadic.

NTC1 in a hole below the UPW50.

NTC2 near the wire of the UPW50 in the 6.5 mm dia hole for the UPW50

Thermal grease is used. Fan is within the plastic cap.

the Z201 is mounted in a smaller aluminium 19.5x19.5x40mm together with NTC3+4

Also with thermal grease.

The results are calculated with linearisation correction for the NTCs.

They do not differ much from all previous results (except for NTC temperature tracking).

So why all the effort? (I hate thermal grease).

Resistance: about -100 ppm @ 25 deg C against Z201 #1

Average T.C. from box method:

Drift UPW50 #1

min -38.96856779

max 33.85651927

diff 72.82508706

temperature

min 8.778501769

max 45.22255957

diff 36.4440578

T.C. = 1.99827054

so average T.C. from box method = 2.0 ppm/K

Regression curve:

T.C. Curve = A0 + A1 * t + A2 * t * t + A3 * t * t * t with: t = (Temp - 25 deg C)

A 0 = -1.1959881148839021E+0000

A 1 = 2.0982250580817275E+0000

A 2 = -2.3221150504742209E-0002

A 3 = -5.7552059855277272E-0005

max. deviation to regression curve: 1.7295248354935827E+0000

So measured T.C. at 25 degrees is again 2.1 ppm / K. (= A1)

Hysteresis not changed against previous measurements.

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UPW50 #2 1K 0.1% Datecode 0841 resistor value @25 deg about -580 ppm against Z201#1

Measurement of 17.08.2014: (slow ramp 0.12 deg / minute)

Average T.C. from box method: +0.59 ppm/K

Regression curve:

T.C. Curve = A0 + A1 * t + A2 * t * t + A3 * t * t * t with: t = (Temp - 25 deg C)

A 0 = -2.80998469524063E-0001

A 1 = 6.29693967898549E-0001

A 2 = -1.70300759394405E-0002

A 3 = 1.32133545088887E-0004

max. deviation to regression curve: 2.02996451023940E+0000 (hysteresis + noise)

So measured T.C. at 25 degrees is +0.63 ppm/K

So UPW50#2 has only 1/3 of the T.C. of UPW#1

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UPW50 #3 1K 0.1% Datecode 1220 resistor value @25 deg about -100 ppm against Z201#1

Measurement of 23.08.2014: (slow ramp 0.12 deg / minute)

Average T.C. from box method: +1.85 ppm/K

Regression curve:

T.C. Curve = A0 + A1 * t + A2 * t * t + A3 * t * t * t with: t = (Temp - 25 deg C)

A 0 = 5.45175269191540E-0001

A 1 = 1.95948365674911E+0000

A 2 = -1.56801576131755E-0002

A 3 = -1.03623042954573E-0004

max. deviation to regression curve: 2.02918100035813E+0000 (hysteresis + noise)

So measured T.C. at 25 degrees is +1.96 ppm/K

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UPW50 #4 1K 0.1% Datecode 1345 resistor value @25 deg about -50 ppm against Z201#1

Measurement of 28.08.2014: (slow ramp 0.12 deg / minute)

Average T.C. from box method: +4.76 ppm/K

Regression curve:

T.C. Curve = A0 + A1 * t + A2 * t * t + A3 * t * t * t with: t = (Temp - 25 deg C)

A 0 = -9.06731926559255E-0001

A 1 = 5.09683804579340E+0000

A 2 = -2.83692334469616E-0002

A 3 = -4.77182333446752E-0004

max. deviation to regression curve: 2.41485072237296E+0000 (hysteresis + noise)

So measured T.C. at 25 degrees is +5.10 ppm/K

This candidate is also one (the first wire wound) where a ageing drift of about 1.2ppm in 3 days is visible.

Maybe due to the high T.C. value.