Understanding How a Meter Read is Calculated - IMR and Multipliers
Roles: Admin, Billing Manager, Technician
Last updated: January 2020
A meter read from a pulse-output meter must be calculated based on the weight of a pulse (multiplier or count factor) added to a known start point when pulses began to be recorded (Initial Meter Read or IMR).
What is an Initial Meter Read (IMR)?
The IMR is the current meter read at the time a Transceiver is first connected to the meter. It is entered into the NextCentury system to serve as a baseline on which usage captured by the Transceiver is added to. If the Transceiver is ever reset/replaced, then this step is repeated and a new IMR is entered.
Why does an IMR need to be recorded?
An IMR needs to be recorded because a pulse-output meter does not output a meter read.
What it does output is a "pulse" that corresponds with a set amount of usage. If a reading device is present (such as the TR201 Transceiver) then pulses can be detected when they occur and be added up. It is by collecting the increasing count of pulses over time that the usage can be calculated.
The Transceiver is typically not installed when a meter's read is exactly at "0". As such, the usage the Transceiver records needs to be added to the usage that was present before the Transceiver was installed- the IMR. If a Transceiver is ever reset or replaced, then this step of recording an IMR needs to be repeated.
I have heard of an Initial Meter Count (IMC), how is it different than an "IMR"?
Some meter reading systems refer to an Initial Meter Count or IMC. This method of recording the meter's prior usage takes into account the meter's multiplier. In essence, the IMC is the number of pulses that a reading device would have recorded if it had been connected since the time the meter was brand new with a read of "0".
In the NextCentury system, an Initial Meter Read (IMR) is the method used for recording the meter's prior usage. This method is simpler as no calculation needs to be performed. Simply enter the read of the meter when the Transceiver is first installed or after it has been reset.
If the IMR is not correct, will usage still be calculated correctly?
After the Transceiver has been properly installed and programmed, it will begin recording pulses. If a report is run over a date range after the Transceiver began checking-in, then usage will be calculated correctly.
If the IMR has not been entered, the Current Meter Read value in the NextCentury system will only include the usage recorded by the Transceiver after it was installed.
An incorrect or missing IMR can cause complications if a usage discrepancy is ever in question and analyzed. As such, it is always recommended that IMRs be entered accurately.
How many numbers of the meter read do I need to include in the IMR?
Typically, the IMR should be entered with at least the same precision as appears on the main dial read (mechanical meter registers) or LCD screen (electronic registers).
If a water meter has a read of 0002345 Gallons, then the IMR can be entered as 2345.
If the meter has sweep-hands, we can see the current read with even greater precision. In this example, the additional sweep hands give us a full read of 0002345.325 Gallons. The meter read can be rounded and the IMR entered as "2345" Gallons.
If the meter has an electronic LCD display, enter the full read that is displayed. Input the decimal point as it appears on the display.
What is a multiplier?
Note: Other industry terms for multiplier include: count factor, CF, pulse weight, pulse value, and pulse multiplier.
A pulse-output meter generates a "pulse" that corresponds to a set amount of usage. To calculate usage, the NextCentury system multiplies the number of pulses by the Multiplier.
Meter Read= (Pulses * Multiplier) + IMR
Can the multiplier be changed?
Water and Gas Meters:
Water or gas meters with mechanical registers (moving dials) are configured for a set multiplier and cannot be changed. Usually, the multiplier is printed on the meter faceplate, i.e. "1 pulse = 10 gallons".
In a very small number of cases, a metered model may have multiple wiring configurations that result in a different multiplier.
Electric, Run Time Meters:
Some electric meters provide multiple wiring port options which each result in a different multiplier.