Accuracy - EMS WT Series Operation & Installation Manual

2.5. Accuracy

WT-Series is designed and manufactured in a way that its errors (of indication) do not
exceed the maximum permissible errors (MPEs), which is based on accuracy class 2 water
meters. Equipped with electronic devices, WT-Series is designed and manufactured in a
way that significant faults do not occur when it is exposed to the disturbance specified in
Performance tests and tests involving the electronic part of a water meter or its devices,
according to OIML (R 49:2013).
 The MPE for the upper flow rate zone (Q2 ≤ Q ≤ Q4) is ±2 %, for temperatures from
0.1°C to 30 °C, and ±3 % for temperatures greater than 30 °C.
 The MPE for the lower flow rate zone (Q1 ≤ Q < Q2) is ±5 % regardless of the
temperature range.
2.5.1. Reverse flow
WT-Series is not designed to measure reverse flow, and the volume passed during
reverse flow will be subtracted from the indicated volume and the water meter will
record forward flow and reverse flow separately. In addition, the water meter will
withstand accidental flow at a flow rate up to Q3 without deterioration or change its
metrological properties for forward flow.
【Picture 5：Error Chart】
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