| 摘要 |
A method of operating a meter to perform the steps of generating a measu re of real energy consumed, generating a measure of reactive energy consumed, a nd generating, from the real energy and reactive energy measures, a measure of apparent energy consumed. In one embodiment, the real energy and reactive energy measures are provided as integer quantity inputs. Particularly, assume S = kVAh, P = kWh, Q = kVARh, and R = Residue. Respective registers store values of P, [2P + 1], Q, [2Q + 1], and the sum [P2 + Q2]. Initially, the P, Q, and [P2 + Q2] register s are set to zero, while the [2P + 1] and [2Q + 1] registers are initialized t o 1. At the arrival of a P pulse, the value in the [2P +1] register is added t o the [P2 + Q2] register, then the P register is incremented by 1 and the [2P + 1] register is incremented by 2. Exactly the same steps are carried out subsequent to receipt of a Q pulse. A set of registers also is used to store the S and [2S + 1] data, and generation of the S pulses is determined as follows. After arrival of either a P or Q pulse, a trial subtraction of [2S + 1] is made from the [P2 + Q2 ] register. If the subtraction does not cause an underflow, an S pulse is generated, the S register is incremented by 1, and the [2S + 1] register is incremented by 2. If the subtractioncauses an underflow, the (P2 + Q2] register is reset to its previous value, the other registers are not incremented, and no S pulse is generated.
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