A thermocouple doesn't measure the absolute temperature, but only the temperature difference. (Keyword: Cold junction compensation) So in your case you would measure the temperature difference to its internal temperature of 19°C. If everything is in equilibrium that you should see 0mV!
This is not how thermocouples, or cold junction compensation works.
I suggest you read this as a primer.
...
I'm going away in a few days, so not sure when I'm going to have time to test this myself.
So might be best if I just attach it here and get feedback.
So consider this an internal not released try at your own risk if you dare firmware.
It fixes the resistance drift problem, i.e. 1M reading which slowly drifts down to the correct value over time, but only on the 2nd probing, it works fine after power-on and first measurement.
Also, time/date stamping has been added to the logging file.
START 2020/01/04 17 42 9 ID 170800121 INTERVAL 0 sec MAIN SUB-1 SUB-2 Remark No. Date Time Func. Value Unit Func. Value Unit Func. Value Unit 1 2020/01/04 17 42 10 DCV -0.0005 V 2 2020/01/04 17 42 10 DCV 0 V 3 2020/01/04 17 42 10 DCV 0.0003 V 4 2020/01/04 17 42 10 DCV -0.0001 V 5 2020/01/04 17 42 10 DCV -0.0005 V 6 2020/01/04 17 42 11 DCV -0.0022 V 7 2020/01/04 17 42 11 DCV 0.0127 V 8 2020/01/04 17 42 11 DCV 0.002 V 9 2020/01/04 17 42 11 DCV 0 V 10 2020/01/04 17 42 11 DCV 0.0001 V 11 2020/01/04 17 42 12 DCV 0.0002 V 12 2020/01/04 17 42 12 DCV -0.0001 V 13 2020/01/04 17 42 12 DCV -0.0006 V 14 2020/01/04 17 42 12 DCV 0 V 15 2020/01/04 17 42 12 DCV 0.0004 V 16 2020/01/04 17 42 13 DCV 0.0001 V 17 2020/01/04 17 42 13 DCV -0.0001 V 18 2020/01/04 17 42 13 DCV -0.0012 V 19 2020/01/04 17 42 13 DCV 0 V 20 2020/01/04 17 42 13 DCV -0.0008 V 21 2020/01/04 17 42 14 DCV -0.0002 V 22 2020/01/04 17 42 14 DCV 0.001 V 23 2020/01/04 17 42 14 DCV 0.0078 V 24 2020/01/04 17 42 14 DCV 0.0033 V 25 2020/01/04 17 42 14 DCV 0.0006 V |
A thermocouple doesn't measure the absolute temperature, but only the temperature difference. (Keyword: Cold junction compensation) So in your case you would measure the temperature difference to its internal temperature of 19°C. If everything is in equilibrium that you should see 0mV!
This is not how thermocouples, or cold junction compensation works.
I suggest you read this as a primer.
Could you elaborate why you think that this is not true? I could suggest reading this paragraph: https://en.wikipedia.org/wiki/Thermocouple#Physical_principle:_Seebeck_effect
I just tried to put it in simple terms: With temperature difference I meant the integration of the temperature gradient from Tsense to Tref.
...
I'm going away in a few days, so not sure when I'm going to have time to test this myself.
So might be best if I just attach it here and get feedback.
So consider this an internal not released try at your own risk if you dare firmware.
It fixes the resistance drift problem, i.e. 1M reading which slowly drifts down to the correct value over time, but only on the 2nd probing, it works fine after power-on and first measurement.
Also, time/date stamping has been added to the logging file.
The date/time stamp on the data is nice. Too bad the resolution is only to the second. At least you don't have to worry about the accumulated time error when using the O interval. Here is a snippet of a sample at 0 (apparently .2 to .25 a second)
START 2020/01/04 17 42 9
ID 170800121
INTERVAL 0 sec
MAIN SUB-1 SUB-2 Remark
No. Date Time Func. Value Unit Func. Value Unit Func. Value Unit
1 2020/01/04 17 42 10 DCV -0.0005 V
2 2020/01/04 17 42 10 DCV 0 V
3 2020/01/04 17 42 10 DCV 0.0003 V
4 2020/01/04 17 42 10 DCV -0.0001 V
5 2020/01/04 17 42 10 DCV -0.0005 V
6 2020/01/04 17 42 11 DCV -0.0022 V
7 2020/01/04 17 42 11 DCV 0.0127 V
8 2020/01/04 17 42 11 DCV 0.002 V
9 2020/01/04 17 42 11 DCV 0 V
10 2020/01/04 17 42 11 DCV 0.0001 V
11 2020/01/04 17 42 12 DCV 0.0002 V
12 2020/01/04 17 42 12 DCV -0.0001 V
13 2020/01/04 17 42 12 DCV -0.0006 V
14 2020/01/04 17 42 12 DCV 0 V
15 2020/01/04 17 42 12 DCV 0.0004 V
16 2020/01/04 17 42 13 DCV 0.0001 V
17 2020/01/04 17 42 13 DCV -0.0001 V
18 2020/01/04 17 42 13 DCV -0.0012 V
19 2020/01/04 17 42 13 DCV 0 V
20 2020/01/04 17 42 13 DCV -0.0008 V
21 2020/01/04 17 42 14 DCV -0.0002 V
22 2020/01/04 17 42 14 DCV 0.001 V
23 2020/01/04 17 42 14 DCV 0.0078 V
24 2020/01/04 17 42 14 DCV 0.0033 V
25 2020/01/04 17 42 14 DCV 0.0006 V
START,2020/02/02,01:20:24,
ID,170800000,
INTERVAL,001,sec,
,,,MAIN,,,SUB-1,,,SUB-2,,,Remark,
No. ,Date ,Time ,Func. ,Value,Unit,Func. ,Value,Unit,Func. ,Value,Unit,
1,2020/02/02,01:20:25,DCVA,00012.4,mVA,DCV,01.1188,V,DCA,0011.10,mA,,
2,2020/02/02,01:20:26,DCVA,00012.4,mVA,DCV,01.1188,V,DCA,0011.10,mA,,
3,2020/02/02,01:20:27,DCVA,00012.4,mVA,DCV,01.1216,V,DCA,0011.10,mA,,
4,2020/02/02,01:20:28,DCVA,00012.4,mVA,DCV,01.1216,V,DCA,0011.13,mA,,
5,2020/02/02,01:20:29,DCVA,00012.4,mVA,DCV,01.1216,V,DCA,0011.13,mA,,
6,2020/02/02,01:20:30,DCVA,00012.4,mVA,DCV,01.1227,V,DCA,0011.13,mA,,
7,2020/02/02,01:20:31,DCVA,00012.4,mVA,DCV,01.1227,V,DCA,0011.13,mA,,
...
I'm going away in a few days, so not sure when I'm going to have time to test this myself.
So might be best if I just attach it here and get feedback.
So consider this an internal not released try at your own risk if you dare firmware.
It fixes the resistance drift problem, i.e. 1M reading which slowly drifts down to the correct value over time, but only on the 2nd probing, it works fine after power-on and first measurement.
Also, time/date stamping has been added to the logging file.
I'm going away in a few days, so not sure when I'm going to have time to test this myself.
So might be best if I just attach it here and get feedback.
So consider this an internal not released try at your own risk if you dare firmware.
It fixes the resistance drift problem, i.e. 1M reading which slowly drifts down to the correct value over time, but only on the 2nd probing, it works fine after power-on and first measurement.
Also, time/date stamping has been added to the logging file.
Did one day testing of a new firmware (2.03 beta), and data logging is still broken.
After 3900 data points logged (mVA mode, with 1 second interval; not 0 second), it stopped saving correct data.
Remaining 48000 data points, are just periodic repetition of about 11 point, and only differ at the last digit.
(Attachment Link)
The same happens to voltage and current. After 3900 data points they become constants.
everyone here has the same problem as yours sir so good luck convincing Dave to repair 131gw's data logging bugs
everyone here has the same problem as yours sir so good luck convincing Dave to repair 131gw's data logging bugs
It is being worked on. v2.03 did not address that bug at all
everyone here has the same problem as yours sir so good luck convincing Dave to repair 131gw's data logging bugsSoftware development follows the same fundamentals as most everything else....
* Fast
* Cheap
* Quality
..... pick two.
This, at least, should ease fears for most:It is being worked on. v2.03 did not address that bug at all... but there will be some impatient souls who won't be happy.
31.01.2020 21:57 <DIR> FOUND.000
01.01.1601 03:00 0 08240001.CSV
31.01.2020 10:30 1 190 258 20013001.CSV
31.01.2020 21:57 <DIR> .
31.01.2020 21:57 <DIR> ..
31.01.2020 21:57 32 768 FILE0000.CHK
31.01.2020 21:57 32 768 FILE0001.CHK
31.01.2020 21:57 32 768 FILE0002.CHK
31.01.2020 21:57 32 768 FILE0003.CHK
31.01.2020 21:57 32 768 FILE0004.CHK
31.01.2020 21:57 32 768 FILE0005.CHK
31.01.2020 21:57 32 768 FILE0006.CHK
31.01.2020 21:57 32 768 FILE0007.CHK
START,2020/01/30,00:22:27,
...
24513,2020/01/30,22:15:27,DCV,006.692,V,,,,,,,,
$ perl -lne 'm#^\d+,(\d{4}/\d{2}/\d{2},\d{2}:\d{2}):\d{2},DCV,[\d\.+-]+,V,,,,,,,,# and print "$1"' 20013001.CSV | sort | uniq -c | sort -n | awk '$1 != 12'
4 2020/01/30,15:02
7 2020/01/30,00:22
8 2020/01/30,14:57
11 2020/01/30,04:32
11 2020/01/30,07:27
11 2020/01/30,13:37
11 2020/01/30,16:32
453 2020/01/30,22:12
1323 2020/01/30,22:17
1764 2020/01/30,22:16
1770 2020/01/30,22:15
1776 2020/01/30,22:13
1776 2020/01/30,22:14
$
$ egrep -B 1 -A 1 '^[0-9].*,(2020/01/30,15:02|2020/01/30,00:22|2020/01/30,14:57|2020/01/30,04:32|2020/01/30,07:27|2020/01/30,13:37|2020/01/30,16:32|2020/01/30,22:12|2020/01/30,22:17|2020/01/30,22:16|2020/01/30,22:15|2020/01/30,22:13|2020/01/30,22:14):' 20013001.CSV
No. ,Date ,Time ,Func. ,Value,Unit,Func. ,Value,Unit,Func. ,Value,Unit,
1,2020/01/30,00:22:28,DCV,006.579,V,,,,,,,,
2,2020/01/30,00:22:33,DCV,006.579,V,,,,,,,,
3,2020/01/30,00:22:38,DCV,006.580,V,,,,,,,,
4,2020/01/30,00:22:43,DCV,006.580,V,,,,,,,,
5,2020/01/30,00:22:48,DCV,006.578,V,,,,,,,,
6,2020/01/30,00:22:53,DCV,006.579,V,,,,,,,,
7,2020/01/30,00:22:58,DCV,006.580,V,,,,,,,,
8,2020/01/30,00:23:03,DCV,006.581,V,,,,,,,,
--
2995,2020/01/30,04:31:59,DCV,006.555,V,,,,,,,,
2996,2020/01/30,04:32:04,DCV,006.555,V,,,,,,,,
2997,2020/01/30,04:32:09,DCV,006.557,V,,,,,,,,
2998,2020/01/30,04:32:14,DCV,006.555,V,,,,,,,,
2999,2020/01/30,04:32:19,DCV,006.557,V,,,,,,,,
3000,2020/01/30,04:32:24,DCV,006.555,V,,,,,,,,
3001,2020/01/30,04:32:30,DCV,006.556,V,,,,,,,,
3002,2020/01/30,04:32:35,DCV,006.555,V,,,,,,,,
3003,2020/01/30,04:32:40,DCV,006.557,V,,,,,,,,
3004,2020/01/30,04:32:45,DCV,006.555,V,,,,,,,,
3005,2020/01/30,04:32:50,DCV,006.559,V,,,,,,,,
3006,2020/01/30,04:32:55,DCV,006.562,V,,,,,,,,
3007,2020/01/30,04:33:00,DCV,006.559,V,,,,,,,,
--
5094,2020/01/30,07:26:59,DCV,006.664,V,,,,,,,,
5095,2020/01/30,07:27:04,DCV,006.664,V,,,,,,,,
5096,2020/01/30,07:27:09,DCV,006.660,V,,,,,,,,
5097,2020/01/30,07:27:14,DCV,006.665,V,,,,,,,,
5098,2020/01/30,07:27:19,DCV,006.660,V,,,,,,,,
5099,2020/01/30,07:27:24,DCV,006.671,V,,,,,,,,
5100,2020/01/30,07:27:29,DCV,006.659,V,,,,,,,,
5101,2020/01/30,07:27:35,DCV,006.660,V,,,,,,,,
5102,2020/01/30,07:27:40,DCV,006.668,V,,,,,,,,
5103,2020/01/30,07:27:45,DCV,006.666,V,,,,,,,,
5104,2020/01/30,07:27:50,DCV,006.661,V,,,,,,,,
5105,2020/01/30,07:27:55,DCV,006.665,V,,,,,,,,
5106,2020/01/30,07:28:00,DCV,006.667,V,,,,,,,,
--
9533,2020/01/30,13:36:59,DCV,006.813,V,,,,,,,,
9534,2020/01/30,13:37:04,DCV,006.808,V,,,,,,,,
9535,2020/01/30,13:37:09,DCV,006.806,V,,,,,,,,
9536,2020/01/30,13:37:14,DCV,006.810,V,,,,,,,,
9537,2020/01/30,13:37:19,DCV,006.811,V,,,,,,,,
9538,2020/01/30,13:37:24,DCV,006.796,V,,,,,,,,
9539,2020/01/30,13:37:29,DCV,006.806,V,,,,,,,,
9540,2020/01/30,13:37:34,DCV,006.816,V,,,,,,,,
9541,2020/01/30,13:37:40,DCV,006.802,V,,,,,,,,
9542,2020/01/30,13:37:45,DCV,006.810,V,,,,,,,,
9543,2020/01/30,13:37:50,DCV,006.816,V,,,,,,,,
9544,2020/01/30,13:37:55,DCV,006.806,V,,,,,,,,
9545,2020/01/30,13:38:00,DCV,006.809,V,,,,,,,,
--
10492,2020/01/30,14:56:55,DCV,006.827,V,,,,,,,,
10493,2020/01/30,14:57:00,DCV,006.820,V,,,,,,,,
10494,2020/01/30,14:57:05,DCV,006.809,V,,,,,,,,
10495,2020/01/30,14:57:10,DCV,006.808,V,,,,,,,,
10496,2020/01/30,14:57:15,DCV,006.819,V,,,,,,,,
10497,2020/01/30,14:57:20,DCV,006.818,V,,,,,,,,
10498,2020/01/30,14:57:25,DCV,006.815,V,,,,,,,,
10499,2020/01/30,14:57:30,DCV,006.818,V,,,,,,,,
10500,2020/01/30,14:57:35,DCV,006.808,V,,,,,,,,
10501,2020/01/30,15:02:43,DCV,006.824,V,,,,,,,,
10502,2020/01/30,15:02:48,DCV,006.828,V,,,,,,,,
10503,2020/01/30,15:02:53,DCV,006.825,V,,,,,,,,
10504,2020/01/30,15:02:58,DCV,006.819,V,,,,,,,,
...
18397,2020/01/30,22:15:47,DCV,006.692,V,,,,,,,,
18398,2020/01/30,22:15:52,DCV,006.693,V,,,,,,,,
18399,2020/01/30,22:15:57,DCV,006.692,V,,,,,,,,
18400,2020/01/30,22:16:02,DCV,006.692,V,,,,,,,,
18401,2020/01/30,22:16:07,DCV,006.692,V,,,,,,,,
18402,2020/01/30,22:16:12,DCV,006.693,V,,,,,,,,
18403,2020/01/30,22:16:17,DCV,006.693,V,,,,,,,,
18404,2020/01/30,22:16:22,DCV,006.693,V,,,,,,,,
18405,2020/01/30,22:16:27,DCV,006.692,V,,,,,,,,
18406,2020/01/30,22:16:32,DCV,006.694,V,,,,,,,,
18407,2020/01/30,22:16:37,DCV,006.692,V,,,,,,,,
18408,2020/01/30,22:16:42,DCV,006.693,V,,,,,,,,
18409,2020/01/30,22:16:47,DCV,006.693,V,,,,,,,,
18410,2020/01/30,22:16:52,DCV,006.692,V,,,,,,,,
18411,2020/01/30,22:16:57,DCV,006.692,V,,,,,,,,
18412,2020/01/30,22:17:02,DCV,006.693,V,,,,,,,,
18413,2020/01/30,22:17:07,DCV,006.693,V,,,,,,,,
18414,2020/01/30,22:17:12,DCV,006.695,V,,,,,,,,
18415,2020/01/30,22:17:17,DCV,006.694,V,,,,,,,,
18416,2020/01/30,22:17:22,DCV,006.693,V,,,,,,,,
18417,2020/01/30,22:17:27,DCV,006.693,V,,,,,,,,
18418,2020/01/30,22:17:32,DCV,006.689,V,,,,,,,,
18419,2020/01/30,22:17:37,DCV,006.690,V,,,,,,,,
18420,2020/01/30,22:17:42,DCV,006.691,V,,,,,,,,
18421,2020/01/30,22:12:47,DCV,006.692,V,,,,,,,,
18422,2020/01/30,22:12:52,DCV,006.692,V,,,,,,,,
18423,2020/01/30,22:12:57,DCV,006.691,V,,,,,,,,
18424,2020/01/30,22:13:02,DCV,006.691,V,,,,,,,,
18425,2020/01/30,22:13:07,DCV,006.690,V,,,,,,,,
18426,2020/01/30,22:13:12,DCV,006.690,V,,,,,,,,
18427,2020/01/30,22:13:17,DCV,006.688,V,,,,,,,,
18428,2020/01/30,22:13:22,DCV,006.686,V,,,,,,,,
18429,2020/01/30,22:13:27,DCV,006.688,V,,,,,,,,
18430,2020/01/30,22:13:32,DCV,006.689,V,,,,,,,,
18431,2020/01/30,22:13:37,DCV,006.691,V,,,,,,,,
18432,2020/01/30,22:13:42,DCV,006.689,V,,,,,,,,
18433,2020/01/30,22:13:47,DCV,006.689,V,,,,,,,,
18434,2020/01/30,22:13:52,DCV,006.687,V,,,,,,,,
18435,2020/01/30,22:13:57,DCV,006.688,V,,,,,,,,
18436,2020/01/30,22:14:02,DCV,006.688,V,,,,,,,,
18437,2020/01/30,22:14:07,DCV,006.686,V,,,,,,,,
18438,2020/01/30,22:14:12,DCV,006.688,V,,,,,,,,
18439,2020/01/30,22:14:17,DCV,006.689,V,,,,,,,,
18440,2020/01/30,22:14:22,DCV,006.688,V,,,,,,,,
18441,2020/01/30,22:14:27,DCV,006.689,V,,,,,,,,
18442,2020/01/30,22:14:32,DCV,006.689,V,,,,,,,,
18443,2020/01/30,22:14:37,DCV,006.690,V,,,,,,,,
18444,2020/01/30,22:14:42,DCV,006.691,V,,,,,,,,
18445,2020/01/30,22:14:47,DCV,006.691,V,,,,,,,,
18446,2020/01/30,22:14:52,DCV,006.691,V,,,,,,,,
18447,2020/01/30,22:14:57,DCV,006.693,V,,,,,,,,
18448,2020/01/30,22:15:02,DCV,006.693,V,,,,,,,,
18449,2020/01/30,22:15:07,DCV,006.691,V,,,,,,,,
18450,2020/01/30,22:15:12,DCV,006.693,V,,,,,,,,
18451,2020/01/30,22:15:17,DCV,006.693,V,,,,,,,,
18452,2020/01/30,22:15:22,DCV,006.693,V,,,,,,,,
18453,2020/01/30,22:15:27,DCV,006.692,V,,,,,,,,
18454,2020/01/30,22:15:32,DCV,006.691,V,,,,,,,,
18455,2020/01/30,22:15:37,DCV,006.690,V,,,,,,,,
18456,2020/01/30,22:15:42,DCV,006.692,V,,,,,,,,
18457,2020/01/30,22:15:47,DCV,006.692,V,,,,,,,,
18458,2020/01/30,22:15:52,DCV,006.693,V,,,,,,,,
18459,2020/01/30,22:15:57,DCV,006.692,V,,,,,,,,
18460,2020/01/30,22:16:02,DCV,006.692,V,,,,,,,,
...
START,2020/02/01,02:15:47,
ID,170800000,
INTERVAL,000,sec,
,,,MAIN,,,SUB-1,,,SUB-2,,,Remark,
No. ,Date ,Time ,Func. ,Value,Unit,Func. ,Value,Unit,Func. ,Value,Unit,
1,2020/02/01,02:15:48,DCV,007.793,V,,,,,,,,
...
130518,2020/02/01,04:12:27,DCV,007.661,V,,,,,,,,
MAX,33241,DCV,009.202,V,
MIN,3362,DCV,003.239,V,
01.02.2020 09:39 6 415 024 20020100.CSV
02.02.2020 19:39 29 889 125 20020102.CSV
START,2020/02/01,09:49:15,
ID,170800000,
INTERVAL,000,sec,
,,,MAIN,,,SUB-1,,,SUB-2,,,Remark,
No. ,Date ,Time ,Func. ,Value,Unit,Func. ,Value,Unit,Func. ,Value,Unit,
1,2020/02/01,09:49:15,DCV,008.407,V,,,,,,,,
...
600000,2020/02/01,16:09:28,DCV,008.952,V,,,,,,,,
MAX,73741,DCV,009.224,V,
MIN,17209,DCV,003.251,V,
UPDATE:
The issue with the cracked input jacks is as several suspected, a molding issue.Quoteinput jacks which were injected from the uncompletely-cleared mould probably resulting in for ABS mixed with any foreign materials so the injected jacks could be more easily broken.
Units potentially affected are with serial numbers S/N 18087001 to 181008000
The sockets for these were manually inspected for this issue but it seems that some slipped passed the inspection and have resulted in cracking.
They also mention the Brymen leads are not ideal:Quote2. Our input jacks were designed to be ideally matched with our test lead probe with 4.2 - 4.3 phi. However, Brymen's probe has 4.5 - 5.0 phi, which can give more mechanical stresses to our input jacks.
"Phi" means diameter of the banana plug.
I'm not sure about their measurements because I measured the Brymen at 4.3mm or a smidge over. The UEi ones are spot on 4mm and not the lantern type ones the Brymen use.
They aren't saying don't use the Brymen leads, just that could be a contributing factor in this case. Welectron have been supplying Brymen leads.
My new stock of meters will all come with UEi leads.
They will be sending me a bunch of replacement jacks so I can send to people who want that option.
If you have been affected by this and prefer to replace it yourself, please email me your address so I can send you one. Use the email Title "121GW Connector"
Alternatively you send your meter back to UEi at this address. I'm not sure if they will rework or replace the meter or board.
Attn: (Mr.) Heegoo Kang
Tel: 82-32-837-5777
309, A-dong, Smart Valley,
Songdomirae-ro 30, Yeonsu-gu, Incheon,
21990, Korea
Email sent. Thanks Dave!
ST Micom recommended our team to use their library in order to send every 60 data packet stored in the EEPROM built-in the ST micom to the SD card. We found this issue is caused by our using this library. We solved this issue by sending every 60 data packet stored in the RAM, instead of the EEPROM, built-in the ST micom to the SD card.
F/W ver 2.02. The current shown in the VA mode is incorrect. See attached image for details.
With the same source and the load the 121GW on the left which is in the VA mode is showing 4.8208mA and the one on the right which is in the A mode is showing 10.415mA (correct value verified with a Fluke 287).
Please investigate this. Mux-ed ADC issue ?.
That is interesting and I hadn't seen any glitches in the logs I collected during testing and playing with it initially or with some of the later firmware (generally I don't use the 121GW for that much due to other gear available).