71M6543F Datasheet, PDF (26/157 Pages) Maxim Integrated Products – Selectable Gain of 1 or 8 for One Current Energy Meter ICs Metrology Compensation

71M6543F/H and 71M6543G/GH Data Sheet
2.3.4 Meter Equations
The 71M6543 provides hardware assistance to the CE in order to support various meter equations. This
assistance is controlled through I/O RAM field EQU[2:0] (equation assist, I/O RAM 0x2106[7:5]). The
Compute Engine (CE) firmware configurations can implement the equations listed in Table 7. EQU[2:0]
specifies the equation to be used based on the meter configuration and on the number of phases used for
metering.
Table 7: Inputs Selected in Multiplexer Cycles
EQU[2:0]*
Description
Wh and VARh formula
Recommended
Element 0 Element 1 Element 2 ^{Multiplexer Sequence}
2
2-element, 3-W, 3φ Delta VA ∙ IA
VB ∙ IB
N/A
IA VA IB VB
3
2-element, 4-W, 3φ Delta VA(IA-IB)/2 VC ∙IC
N/A
IA VA IB VB IC VC
4
2-element, 4-W, 3φ Wye VA(IA-IB)/2 VB(IC-IB)/2 N/A
IA VA IB VB IC VC
5
3-element, 4-W, 3φ Wye VA ∙ IA
VB ∙ IB
VC ∙ IC IA VA IB VB IC VC (ID)
Note:
* Only EQU[2:0] = 5 is supported by the currently available CE code versions for the 71M6543. Contact
your local Teridian representative for CE codes that support equations 2, 3 and 4.
2.3.5 Real-Time Monitor (RTM)
The CE contains a Real-Time Monitor (RTM), which can be programmed to monitor four selectable XRAM
locations at full sample rate. The data from the four monitored locations are serially output to the TMUXOUT
pin via the digital output multiplexer at the beginning of each CE code pass. The RTM can be enabled and
disabled with RTM_E (I/O RAM 0x2106[1]). The RTM output clock is available on the TMUX2OUT pin. Each
RTM word is clocked out in 35 cycles and contains a leading flag bit. See Figure 8 for the RTM output
format. RTM is low when not in use.
CK32
MUX_SYNC
MUX_STATE
CKTEST
RTM
FLAG
RTM DATA0 (32 bits)
RTM DATA1 (32 bits)
RTM DATA2 (32 bits)
RTM DATA3 (32 bits)
0 1 30 31
FLAG
S
0 1 30 31
FLAG
0 1 30 31
FLAG
0 1 30 31
Figure 8: RTM Timing
2.3.6 Pulse Generators
The 71M6543 provides four pulse generators, VPULSE, WPULSE, XPULSE and YPULSE. The XPULSE
and YPULSE generators are used by standard CE code to output CE status indicators, for example the
status of the sag detection, to DIO pins. All pulses can be configured to generate interrupts to the MPU.
The polarity of the pulses may be inverted with PLS_INV (I/O RAM 0x210C[0]). When this bit is set, the
pulses are active high, rather than the more usual active low. PLS_INV inverts all the pulse outputs.
The function of each pulse generator is determined by the CE code and the MPU code must configure the
corresponding pulse outputs in agreement with the CE code. For example, standard CE code produces a
mains zero-crossing pulse on XPULSE and a SAG pulse on YPULSE.
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