K8055 Voltage Recorder

Voltage Labo Results

I performed several tests to verify the accuracy of my voltage recorder. The tests were done on a modified version of the k8055: I bypassed the resistors R3 and R4, and added a 330k resistor for R8 and R9.

Measurement 1: voltage between 0 and 5 VDC

I did a first measurement to test the accuracy when measuring a voltage between 0 and 5 VDC. This voltage was applied directly to the connector SK1. I varied the input voltage in steps of 100 mV.

Conclusion: I found a maximum measuring error of 2.04%. The average measuring error was only 0.77%. These results are acceptable.

Vset (V)	Vmeas (V)	Vdiff (V)	diff (%)
0.00	0.000	0.000	0.00
0.10	0.098	-0.002	2.04
0.20	0.196	-0.004	2.04
0.30	0.294	-0.006	2.04
0.40	0.392	-0.008	2.04
0.50	0.490	-0.010	2.04
0.60	0.608	0.008	1.32
0.70	0.706	0.006	0.85
0.80	0.804	0.004	0.50
0.90	0.902	0.002	0.22
1.00	1.000	0.000	0.00
1.10	1.098	-0.002	0.18
1.20	1.196	-0.004	0.33
1.30	1.314	0.014	1.07
1.40	1.412	0.012	0.85
1.50	1.510	0.010	0.66
1.60	1.588	-0.012	0.76
1.70	1.706	0.006	0.35
1.80	1.804	0.004	0.22
1.90	1.902	0.002	0.11
2.00	2.020	0.020	0.99
2.10	2.118	0.018	0.85
2.20	2.216	0.016	0.72
2.30	2.314	0.014	0.61
2.40	2.412	0.012	0.5
2.50	2.529	0.029	1.15
2.60	2.608	0.008	0.31
2.70	2.706	0.006	0.22
2.80	2.804	0.004	0.14
2.90	2.922	0.022	0.75
3.00	3.020	0.020	0.66
3.10	3.118	0.018	0.58
3.20	3.216	0.016	0.50
3.30	3.314	0.014	0.42
3.40	3.431	0.031	0.90
3.50	3.529	0.029	0.82
3.60	3.627	0.027	0.74
3.70	3.725	0.025	0.67
3.80	3.824	0.024	0.63
3.90	3.922	0.022	0.56
4.00	4.039	0.039	0.97
4.10	4.137	0.037	0.89
4.20	4.235	0.035	0.83
4.30	4.333	0.033	0.76
4.40	4.431	0.031	0.70
4.50	4.549	0.049	1.08
4.60	4.647	0.047	1.01
4.70	4.745	0.045	0.95
4.80	4.843	0.043	0.89
4.90	4.941	0.041	0.83
5.00	5.000	0.000	0.00

Measurement 2: voltage between 0 and 10 VDC

I also tested the accuracy of the logger with an input voltage between 0 and 10 VDC. The K8055's maximum input voltage is 5 V so I needed to add an external resistor of 100 kOhm. I varied the input voltage in steps of 250 mV, because the measuring resolution is now worse (39.2 mV).

Conclusion: I found a maximum measuring error of 9.09% but this error occured at a very low voltage. The average deviation was about 0.98%. This means the results are acceptable.

Vset (V)	Vmeas (V)	Vdiff (V)	diff (%)
0.00	0.000	0.000	0.00
0.25	0.275	0.025	9.09
0.50	0.471	-0.029	6.16
0.75	0.745	-0.005	0.67
1.00	0.980	-0.020	2.04
1.25	1.255	0.005	0.40
1.50	1.490	-0.010	0.67
1.75	1.725	-0.025	1.45
2.00	2.000	0.000	0.00
2.25	2.235	-0.015	0.67
2.50	2.471	-0.029	1.17
2.75	2.745	-0.005	0.18
3.00	3.020	0.020	0.66
3.25	3.255	0.005	0.15
3.50	3.490	-0.010	0.29
3.75	3.765	0.015	0.40
4.00	4.000	0.000	0.00
4.25	4.235	-0.015	0.35
4.50	4.510	0.010	0.22
4.75	4.745	-0.005	0.11
5.00	5.020	0.020	0.40
5.25	5.255	0.005	0.10
5.50	5.529	0.029	0.52
5.75	5.765	0.015	0.26
6.00	6.039	0.039	0.65
6.25	6.275	0.025	0.40
6.50	6.549	0.049	0.75
6.75	6.784	0.034	0.50
7.00	7.059	0.059	0.84
7.25	7.373	0.123	1.67
7.50	7.569	0.069	0.91
7.75	7.804	0.054	0.69
8.00	8.078	0.078	0.97
8.25	8.314	0.064	0.77
8.50	8.588	0.088	1.02
8.75	8.824	0.074	0.84
9.00	9.098	0.098	1.08
9.25	9.333	0.083	0.89
9.50	9.608	0.108	1.12
9.75	9.843	0.093	0.94
10.00	10.000	0.000	0.00

Measurement 3: voltage between 0 and 30 VDC

I did a final measurement with a variable voltage between 0 and 30 VDC. I used an external resistance of 503 kOhm. With this value the maximum input voltage was 30.15 V while the resolution was 118.2 mV.

Conclusion: I found a maximum measuring error of 5.40%. This error occured at very low voltages, just like with the other experiments. The average deviation was only 1.25 %.

Vset (V)	Vmeas (V)	Vdiff (V)	diff (%)
0.50	0.473	0.027	5.40
1.00	0.946	0.054	5.40
1.50	1.419	0.081	5.40
2.00	2.01	-0.010	0.50
2.50	2.365	0.135	5.40
3.00	2.956	0.044	1.47
3.50	3.429	0.071	2.03
4.00	4.020	-0.020	0.50
4.50	4.493	0.007	0.16
5.00	4.966	0.034	0.68
5.50	5.557	-0.057	1.04
6.00	6.03	-0.030	0.50
6.50	6.503	-0.003	0.05
7.00	7.094	-0.094	1.34
7.50	7.449	0.051	0.68
8.00	8.040	-0.040	0.50
8.50	8.513	-0.013	0.15
9.00	9.104	-0.104	1.16
9.50	9.577	-0.077	0.81
10.0	10.050	-0.050	0.50
10.5	10.523	-0.023	0.22
11.0	11.114	-0.114	1.04
11.5	11.587	-0.087	0.76
12.0	12.060	-0.060	0.50
12.5	12.533	-0.033	0.26
13.0	13.124	-0.124	0.95
13.5	13.597	-0.097	0.72
14.0	14.070	-0.070	0.50
14.5	14.661	-0.161	1.11
15.0	15.134	-0.134	0.89
15.5	15.725	-0.225	1.45
16.0	16.198	-0.198	1.24
16.5	16.671	-0.171	1.04
17.0	17.144	-0.144	0.85
17.5	17.735	-0.235	1.34
18.0	18.208	-0.208	1.16
18.5	18.681	-0.181	0.98
19.0	19.154	-0.154	0.81
19.5	19.745	-0.245	1.26
20.0	20.218	-0.218	1.09
20.5	20.691	-0.191	0.93
21.0	21.164	-0.164	0.78
21.5	21.755	-0.255	1.19
22.0	22.228	-0.228	1.04
22.5	22.701	-0.201	0.89
23.0	23.292	-0.292	1.27
23.5	23.765	-0.265	1.13
24.0	24.356	-0.356	1.48
24.5	24.829	-0.329	1.34
25.0	25.302	-0.302	1.21
25.5	25.775	-0.275	1.08
26.0	26.366	-0.366	1.41
26.5	26.839	-0.339	1.28
27.0	27.312	-0.312	1.16
27.5	27.904	-0.404	1.47
28.0	28.376	-0.376	1.34
28.5	28.849	-0.349	1.22
29.0	29.322	-0.322	1.11
30.0	30.15	-0.150	0.50