Aclara I-210+ - Real Time Watt Hour Disk Emulator

I-210+ User Manual 17
Chapter 3 • Operating Instructions
Real Time Watt Hour Disk Emulator
The I-210+ meter display contains a three-segment real-time disk- analog display
(caterpillar) that is intended to emulate the motion of an electromechanical meter
disk. The states of the disk-analog display are sequenced to give the appearance of
left-to-right motion of the disk timing mark when the energy flow is in the
delivered direction. The apparent direction of motion will reverse when energy
flow is in the received direction regardless of the energy accumulation option that
was selected. The Delivered and Received annunciators will also indicate the
direction of energy flow.
The disk-analog completes one apparent revolution when the meter accumulates
Kh watt-hours. This is consistent with the meaning of Kh used in
electromechanical watt-hour metering.
The disk-analog simulates motion by sequencing through a series of related
display states. The disk-analog display will advance by one display state whenever
the meter generates a test pulse (i.e., Kt watt-hours are accumulated). So the Kh of
the disk analog and the Kt of the test pulse are always related in the I-210+ meter
by the expression Kh = 10 x Kt .
The values of Kh and Kt were chosen for the available forms of I-210+ to provide
a consistent rate of rotation for all meter types operating at the same percent of
class rating. For example, the apparent rotation rate will be the same for a class
200 meter and a class 20 meter, each running at test amperage.
Because the disk-analog is a real-time display it can be used in conjunction with a
stopwatch to estimate the current meter load. In addition, if you have enabled the
instantaneous power display, this information is accurately reported in numeric
form by the instantaneous kW display of the I-210+ meter.
The following diagram illustrates the display states of the watt-hour disk emulator.
The disk analog has 10 states, 5 of which are invisible. The following diagram
shows what you will see on the display and what it represents in watt-hours when
Kt equals 1 and energy is being delivered. Each state represents 10% of the Kh
value. The flow of the disk indicators is from right to left when energy is being
received. Refer to the Physical Variants Available section on page 6 for Kt values.