Measurement of the parameters of cables for intrinsically safe Fieldbus (FISCO). Non-destructive control of cables of arbitrary length

Electrical parameters of the cables of intrinsically safe Fieldbus (FISCO), the primary parameters of the cables, to methods of measurement were researched by authors. It is established that measurements of the inductance of the cables should be performed on the sample with a length of 100 m. This restriction eliminates the possibility of nondestructive testing of cable products. The error of the traditional method of measuring the primary parameters was analyzed. The proposed factors of restoration of the true values of inductance and capacitance on the measurement results of samples with lengths greater than 100 m. Presents formulas allowing defining the parameters of the cables of arbitrary length. In article were demonstrate the results of practical measurements of the cables.
Materials and methods
The analysis of normative documents. Analysis of measurement errors. The output formulas. Pilot study.
Results
It were shown the limitations of the traditional method of measuring linear parameters using RLC-meters. The values of factors of restoration, allowing to specify the values of capacitance and inductance values, the traditional method measured by RLC-meter were considered. The algorithm and formulas to accurately determine the coefficients of recovery for any cables were obtained.
Сonclusions
We presented free from restrictions on the length of the sample cable is a systematic method of measurement. Also was demonstrated the possibility of obtaining undistorted values of the parameters of the cables with length up to 5000 m in accordance with GOST R IEC 60079-27-2012. Proposed system the method of measurement is:
• eliminates the inherent traditional method limits the maximum length of the monitored cable previously installed in the standard equal to 100 m in the measurement of inductance and defined in the researchis 1600...2400 m in the measurement of capacitance;
• provides the ability to sample any drumto control; no need to pay attention to the length of the cable on the drum, nor to cut off from it for clearance measurements a piece of 100 meters;
• ensures the implementation of non-destructive control of linear capacitance, running inductance, and the ratio L/R ofany construction lengths of cables, as in RVfactories and on the sites of customers;
• supported by a commercially producedanalyzer AnCom A-7/307;
• allows you to measure and to compare with the norms of primary and secondary parameters (its own attenuation factor and the impedance of the cables) in one process.