71M6541F Maxim, 71M6541F Datasheet - Page 16

• Manufacturer Part Number: 71M6541F
• Description: The 71M6541D/71M6541F/71M6541G/71M6542F/71M6542G are Teridian™ 4th-generation single-phase metering SoCs with a 5MHz 8051-compatible MPU core, low-power RTC with digital temperature compensation, flash memory, and LCD driver
• Manufacturer: Maxim

71M6541D/F/G and 71M6542F/G Data Sheet
For a basic single-phase application, the IAP-IAN current input is configured for differential mode,
whereas the VA pin is single-ended and is typically connected to the phase voltage via a resistor divider.
The IBP-IBN differential input may be optionally used to sense the Neutral current. This configuration
implies that the multiplexer applies a total of three inputs to the ADC. For this configuration, the
multiplexer sequence is as shown in
sampled, the extra conversion time slot (i.e., slot 2) is the optional Neutral current, and the physical
current sensor for the Neutral current measurement may be omitted if not required.
For a standard single-phase application with tamper sensor in the neutral path, two current inputs can be
configured for differential mode, using the pin pairs IAP-IAN and IBP-IBN. This means that the multiplexer
applies a total of three inputs to the ADC. In this application, the system design may use two locally
connected current sensors via IAP-IAN and IBP-IBN, as shown in
inputs. Alternately, the IAP-IAN pin pair is configured as a differential input and connected to a local current
shunt, and IBP-IBN is configured to connect to an isolated 71M6x01 isolated sensor (i.e., RMT_E = 1), as
shown in
configuration, the multiplexer frame is also as shown in
the CE, as the samples corresponding to the remote sensor (IBP-IBN) do not pass through the
multiplexer and are stored directly in CE RAM. The remote current sensor channel is sampled during the
second half of the multiplexer frame and its timing relationship to the VA voltage is precisely known so
that delay compensation can be properly applied.
The 71M6542F adds the ability to sample a second phase voltage (applied at the VB pin), which makes it
suitable for meters with two voltage and two current sensors, such as meters implementing Equation 2 for
dual-phase operation (P = VA*IA+VB*IB).
16
Figure
Using settings for the I/O RAM Mnemonics listed in
those required by the corresponding CE code being used results in undesirable side effects
and must not be selected by the MPU. Consult your local Teridian representative to obtain
the correct CE code and AFE / MUX settings corresponding to the application.
Notes:
Teridian updates the CE code periodically. Please contact your local Teridian representative to
obtain the latest CE code and the associated settings. The configuration presented in this table is
set by the MPU demonstration code during initialization.
Current Sensor Type
Table 2. Required CE Code and Settings for 71M6x01 isolated Sensor
Applicable Figure
3. The VA pin is typically connected to the phase voltage via resistor dividers. For this
MUX2_SEL[3:0]
MUX3_SEL[3:0]
MUX0_SEL[3:0]
MUX1_SEL[3:0]
MUX_DIV[3:0]
1.
2.
3.
FIR_LEN[1:0]
Mnemonic
PLL_FAST
Equations
ADC_DIV
EQU[2:0]
DIFFA_E
DIFFB_E
CE Code
I/O RAM
RMT_E
Although not used, set to 1 (the sample data is ignored by the CE)
71M654x with 71M6201 remote sensor (200 Amps)
71M654x with 71M6601 remote sensor (60 Amps)
1
1
Figure
210C[2:1]
Location
2100[7:4]
2105[3:0]
2105[7:4]
2104[3:0]
2104[7:4]
2106[7:5]
I/O RAM
210C[4]
210C[5]
2200[5]
2200[4]
2709[3]
Figure 7
6. In this configuration IAP-IAN, IBP-IBN and VA are
--
--
--
--
shows the multiplexer sequence when four inputs are
1 Remote Shunt
71M6541D/F/G
1 Local Shunt
Figure 6
Figure 3
0 or 1
(hex)
0, 1
and
A
1
1
1
3
0
1
1
1
1
0
Table 1
and time slot 2 is unused and ignored by
Figure
CE41B016201
CE41B016601
and
2, and configured as differential
1 Remote Shunt
Table 2
1 Local Shunt
71M6542F/G
0, 1 and 2
0, 1 or 2
Figure 5
2
3
(hex)
and
A
1
1
1
3
0
9
1
1
1
0
that do not match
Rev 2