Molbox 1 A700K — Drift Analysis

Drift analysis and trend monitoring for Molbox 1 A700K.

Assessment

TODO: Review drift history and write metrological assessment.

Internal Specification: Analyt MTC — identical to manufacturer spec (Fluke as-found with 1-year drift)

Manufacturer Specification: Fluke Calibration certificates 1500149737 (2013) and 1500224220 (2017) — pressure: max(0.01% rdg, 0.003% of 700 kPa FS) + 0.005% FS/year; resistance: ±0.04Ω (±0.05°C for one year)

Pressure Downstream (mbar)

Setpoint (mbar)20102011201220132014201520162018
AdjustedYesYesYesYesYesYesYes
As-found Dev/Spec — measured error normalized to internal specification
200-0.64-0.28-0.67
350-0.46-0.69
550-0.37-0.55
1000-0.24+0.18-0.17
1100-0.20-0.28
1650-0.13-0.14
2000-0.13+0.27-0.12
2200-0.15-0.09
2750-0.18-0.10
3000-0.16+0.17-0.23
3300-0.18-0.14
3825-0.22-0.17
4375-0.25-0.22
4500-0.26+0.03-0.34
4925-0.24-0.26
5475-0.27-0.25
6000-2.28-0.39-0.45-0.41+0.04-0.31
Inter-calibration drift Dev/Spec (Δ) — change since previous calibration, normalized
200-0.10-0.36
350-0.23
550-0.18
1000+0.11-0.32
1100-0.09
1650-0.01
2000+0.13-0.33
2200+0.06
2750+0.08
3000+0.10-0.31
3300+0.04
3825+0.05
4375+0.03
4500+0.09-0.27
4925-0.01
5475+0.02
6000-0.31-0.37-0.35+0.07-0.24

Figure 1 shows each calibration's as-found deviation normalized to the internal specification. Values at ±1.0 reach the specification limit. The shaded blue envelope covers the full spread across all setpoints; the amber band adds measurement uncertainty (RSS). For the full methodology, see Equipment Monitoring & Drift Analysis.

Figure 1. Pressure Downstream Drift Trend

Figure 2 shows the drift between consecutive calibrations — how much the device changed since it was last calibrated or adjusted. This isolates the device’s instability from corrections applied during calibration.

Figure 2. Pressure Downstream — Drift Between Calibrations

Pressure Upstream (mbar)

Setpoint (mbar)20102011201220132014201520162018
AdjustedYesYesYesYesYesYesYes
As-found Dev/Spec — measured error normalized to internal specification
200-0.44+0.03-0.27
350-0.70-0.36
550-0.52-0.28
1000-0.21+0.37-0.01
1100-0.26-0.13
1650-0.17-0.07
2000-0.11+0.59+0.07
2200-0.22-0.07
2750-0.26-0.10
3000-0.13+0.55-0.02
3300-0.28-0.14
3825-0.32-0.17
4375-0.35-0.22
4500-0.22+0.45-0.15
4925-0.35-0.26
5475-0.37-0.26
6000-2.10-0.30-0.50-0.15+0.48-0.16
Inter-calibration drift Dev/Spec (Δ) — change since previous calibration, normalized
200+0.20-0.09
350+0.34
550+0.24
1000+0.32-0.07
1100+0.12
1650+0.10
2000+0.45-0.09
2200+0.15
2750+0.16
3000+0.47-0.10
3300+0.14
3825+0.15
4375+0.13
4500+0.51-0.10
4925+0.09
5475+0.11
6000-0.25-0.45-0.09+0.53-0.10

Figure 3 shows each calibration's as-found deviation normalized to the internal specification. Values at ±1.0 reach the specification limit. The shaded blue envelope covers the full spread across all setpoints; the amber band adds measurement uncertainty (RSS). For the full methodology, see Equipment Monitoring & Drift Analysis.

Figure 3. Pressure Upstream Drift Trend

Figure 4 shows the drift between consecutive calibrations — how much the device changed since it was last calibrated or adjusted. This isolates the device’s instability from corrections applied during calibration.

Figure 4. Pressure Upstream — Drift Between Calibrations

Resistance (Ω)

Setpoint (Ω)20102011201220132014201520162018
AdjustedYesYesYesYesYesYesYes
As-found Dev/Spec — measured error normalized to internal specification
100+0.00+0.00+0.00+0.08-17.04
110+0.00+0.00+0.00+0.24
115
Inter-calibration drift Dev/Spec (Δ) — change since previous calibration, normalized
100+0.00+0.00+0.08-17.12
110+0.00+0.00+0.24
115

Figure 5 shows each calibration's as-found deviation normalized to the internal specification. Values at ±1.0 reach the specification limit. The shaded blue envelope covers the full spread across all setpoints; the amber band adds measurement uncertainty (RSS). For the full methodology, see Equipment Monitoring & Drift Analysis.

Figure 5. Resistance Drift Trend

Figure 6 shows the drift between consecutive calibrations — how much the device changed since it was last calibrated or adjusted. This isolates the device’s instability from corrections applied during calibration.

Figure 6. Resistance — Drift Between Calibrations