Byte-sized Topic: Digital Meters

April 5, 2017

digital meters

Digital meters are the precise monitoring devices of power distribution systems:

  • They provide the maintenance team or facility management staff with electrical consumption levels in different of a system;
  • They enable identification of root causes, such as 1) harmonics which make fluorescent lamps flickering 2) voltage sags which make compressor motors often burning or trips. Meters do so by identifying improper electrical characteristics in the network;
  • They provide modern abilities to communicate energy consumption, current, voltages (and many more information) across an entire industrial site, into a database server, so that maintenance or process engineers can understand what is going wrong, for example why line 2 consumes much more than line 1 for the same production schedule, etc.;
  • Most important, monitoring electrical consumption is the first task to any energy efficiency initiative.

  • Meters usually connect directly or via transformer (such as Current Transformer or Voltage Transformer) to the electrical network phases (L1, L2, L3, Neutral).

    Three examples of digital meters implementation

    1. In a shopping mall

    digital meters shopping mall

    Metering is used for sub-billing to shopping mall tenants (1 tenant = 1 shop). The supervision collect each tenant consumption and enable monthly billing. It also enables to find out which tenant has abnormal consumption and correct the root cause.

    2. In a factory

    digital meters in factory

    Supervision and remote control system, including metering. Metering is used to monitoring overall factory consumption, but also consumption at the level of a production line, or even at each machine.This enables process engineers and maintenance to benchmark, e.g. line output vs. power consumed.It also enables to identify where electrical issues appear, enabling local maintenance without shutting down the whole production.

    3. In a hospital

    Supervision station:

    digital meters in hospital

    Metering architecture:

    digital meters in hospital

    In a hospital most of the electrical devices are critical: an EEG must always be fully functional in the ICU, air filters must always be supplied with the right voltage in the surgery areas, etc. Also, in a hospital, one of the biggest operational expenses is electricity: monitoring its consumption is the first step to energy efficiency.

    Types of meters

    The key characteristics to select a meter can be listed as follows:

    • Measurement Inputs
    • Digital inputs/outputs type & quantity;
    • Analog inputs/outputs type & quantity;
    • Functions;
    • Measurement;
    • Alarming;
    • Communication protocol;
    • Measurement accuracy

    Major manufacturers of industrial sensors are:

    • Schneider Electric
    • Socomec
    • Circutor
    • Omron