10k Thermistor Look Up Table for an I/Net 7756 (lower board)

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Issue

Table needed for linearizing a 10K thermistors for an I/Net 7756 (lower board)

Product Line

TAC INET

Environment

7756 (lower board)

Cause

Thermistors require the use of a look up table to linearize the data.

Resolution

Thermistor Inputs on a PCU 7756 (lower board)

1. Enter the Temperature data in °C (First Column - 31 entries)
2. Enter the corresponding resistance data in Ohms (Second column - 31 entries)
3. Enter the dissipation constant in milliwatts per °C: 2
4. Low Temperature : -22.11°F (-30.06°C)
5. High Temperature: 247.92°F (119.95°C)
6. Point Value in °F: M=0.00412; b=-22.1138
7. Point Value in °C: M=0.00228913; b=--30.0632065

Look Up Table:

°C	Ohms	Current	Self Htg	Adj °C	Adj °F	VDC	Counts	Adj Cts
120	389	0.000481	0.045052	119.95	247.92	0.187217	1227	65535
100	680	0.000468	0.074521	99.93	211.87	0.318352	2086	56785
90	917	0.000458	0.096177	89.90	193.83	0.419987	2752	52407
80	1258	0.000444	0.12407	79.88	175.78	0.558714	3662	48027
70	1753	0.000425	0.158633	69.84	157.71	0.745767	4887	43643
60	2489	0.0004	0.199471	59.80	139.64	0.996477	6530	39257
55	3045	0.000383	0.223671	54.78	130.60	1.167114	7646	37062
50	3602	0.000368	0.243359	49.76	121.56	1.32407	8677	34869
45	4368	0.000348	0.264484	44.74	112.52	1.520045	9962	32676
40	5326	0.000326	0.283435	39.72	103.49	1.73757	11387	30483
35	6691	0.0003	0.300218	34.70	94.46	2.004374	13136	28292
30	8056	0.000277	0.308878	29.69	85.44	2.230837	14620	26104
28	8777	0.000266	0.311174	27.69	81.84	2.337168	15317	25229
26	9572	0.000255	0.312351	25.69	78.24	2.44533	16025	24355
25	10000	0.00025	0.3125	24.69	76.44	2.5	16384	23918
24	10450	0.000244	0.312349	23.69	74.64	2.555012	16744	23481
22	11420	0.000233	0.311127	21.69	71.04	2.665733	17470	22608
20	12490	0.000222	0.308669	19.69	67.44	2.77679	18198	21735
18	13680	0.000211	0.304953	17.70	63.85	2.888514	18930	20863
16	15000	0.0002	0.3	15.70	60.26	3	19661	19992
14	16470	0.000189	0.29383	13.71	56.67	3.111069	20388	19121
12	18090	0.000178	0.286579	11.71	53.08	3.220007	21102	18250
10	19900	0.000167	0.278241	9.72	49.50	3.327759	21808	17380
8	21920	0.000157	0.268921	7.73	45.92	3.433584	22502	16510
6	24180	0.000146	0.258715	5.74	42.33	3.537156	23181	15641
0	32660	0.000117	0.224329	-0.22	31.60	3.827942	25086	13035
-4	36200	0.000108	0.211999	-4.21	24.42	3.917749	25675	11293
-10	55340	0.0000765	0.162028	-10.16	13.71	4.234772	27753	8694
-14	69000	0.0000633	0.138199	-14.14	6.55	4.367089	28620	6957
-20	97130	0.0000467	0.105789	-20.11	-4.19	4.533277	29709	4350
-30	177200	0.0000267	0.063207	-30.06	-22.11	4.732906	31017	0

This spreadsheet is for a thermistor rated at 10,000 ohms at 25°C.

1. Install a 10K Ohm Resistor in the "B" terminal (consult the TCON for the controller you are using for details)
2. This look up table program is based on using 31 entries
3. The data points do not have to be evenly spaced

Click here to download this in pdf format.

For the look up table to the 7716, 7718, 7728 and a 7756 (upper board), see 10k Thermistor Look Up Tables for a 7716, 7718, 7728 and a 7756 (upper board).