CSA C900.1:21 pdf download – Thermal energy meters — Part 1: General requirements.
3.5 reference conditions set of specified values of influence factors, fixed to ensure valid inter-comparison of results of measurements 3.6 influence quantity quantity, which is not the subject of the measurement, but which influences the value of the measurement and or the indication of the measuring instrument 3.7 influence factors influence quantity having a value within the rated operating conditions 3.8 disturbance influence quantity having a value outside the rated operating conditions 3.9 Types of errors 3.9.1 error (of indication) indication of the measuring instrument minus the conventional true value of the measurand 3.9.2 intrinsic error error of a measuring instrument determined under reference conditions 3.9.3 initial intrinsic error error of a measuring instrument as determined once prior to performance tests and durability tests 3.9.4 durability error difference between the intrinsic error after a period of use and the initial intrinsic error 3.9.5 maximum permissible error MPE highest values of the error (positive or negative) permitted 3.10 Types of faults 3.10.1 fault difference between the error of indication and the intrinsic error of the instrument 3.10.2 transitory fault momentary variations in the indication, which cannot be interpreted, memorized or transmitted as measurements
3.10.3 significant fault fault greater than the absolute value of the MPE and not being a transitory fault Note 1 to entry: If the MPE is ± 2 % then the significant fault is a fault larger than ± 2 %. 3.11 reference values of the measurand RVM specified value of the flow rate, the outlet temperature and the temperature difference, fixed to ensure valid intercomparison of the results of measurements 3.12 conventional true value quantity value attributed by agreement to a quantity for a given purpose Note 1 to entry: A conventional true value is, in general, regarded as sufficiently close to the true value for the difference to be insignificant for the given purpose. EXAMPLE A true value is the heat coefficient according to Annex A.
3.22 pulse output and input devices 3.22.1 pulse output device functional part of flow sensor, calculator or auxiliary devices EXAMPLE Remote displays or input devices of control systems. 3.22.2 pulse input device functional part of flow sensor, calculator or auxiliary devices EXAMPLE Remote displays or input devices of control systems. 3.23 maximum admissible temperature maximum temperature of the heat conveying liquid the meter can withstand in combination with the maximum admissible working pressure and the permanent flow rate for short periods of time (< 1 h / day; < 200 h / year) without a significant fault after the exposure to this maximum admissible temperature 3.24 durability characteristic of a measuring instrument to keep the metrological characteristics over time (e.g. to fulfil the double of MPE), provided that it is properly installed, maintained and used within the permissible environmental conditions 3.25 long life flow sensor flow sensor designed to have a longer lifetime than a normal flow sensor, which typically has a durability of 5 years under the specified operating conditions 3.26 user interface interface forming part of the instrument that enables information to be passed between a human user and the measuring instrument or its components (e.g. display) 3.27 communication interface electronic, optical, radio or other technical interface that enables information via correct transceiving of at least thermal energy to be passed between measuring instruments, sub-assemblies or external devices
3.29 registration device an optional additional device fitted to the meter as an integral part or separate device, in order to register the amount of thermal energy accumulated in additional registers during periods, depending on conditions, e. g. flow rate, inlet or outlet temperatures, temperature differences or time points 3.30 register component of a registration device which contains accumulated or actual values e. g. thermal energy, volume, maximum flow rate, power or temperature 3.31 interval register register which contains frequently accumulated or copied values used for registration of billing purposes and/ or for controlling processes Note 1 to entry: During consecutive time intervals values could be achieved by copying from an accumulating main register which contains actual values of e.g. thermal energy or volume. Note 2 to entry: During consecutive time intervals the measured process values of flow rate and/or temperature could be additionally stored. 3.32 maximum flow highest rate of flow which is expected at operating conditions Note 1 to entry: For the limits of flow rates, see 5.3.CSA C900.1:21 pdf download.
