Maxim Integrated 6612_OMU_S2_URT_V1_13 - Manual (Page 17)

FDD_6612_ 010 6612_OMU_S2_URT_V1_13 Firmware Description Document
Rev. 1.1 17
5 MPU Measurement Outputs
This section describes the measurement outputs that can be obtained. Energy outputs are accumulated
numbers. The default accumulation interval is 1 second (999.75 ms). The host accessing the
measurement information from the 78M6612 more frequently will not result in any update in the
information. The accumulation interval is set by the following:
0.01666 * SUM_CYCLES[5:0] (in seconds) where SUM_CYCLE[5:0] are register bits in the I/O RAM that
can be between 15d and 63d (default is 60d). SUM_CYCLES must never be set below 15 (0.250
seconds).
The user can reduce the accumulation cycle with the RI command. To reduce the accumulation interval
to 0.5 seconds, enter the following via the UART:
RI1=+30
A )U command will preserve the new accumulation value across power resets, by writing them to flash.
Table 2 lists the Narrowband outputs for Outlet 1.
Table 2: Outlet 1 MPU Outputs for Narrowband Method
Output
Location
(hex)
LSB Comment Example
Delta
Temperature
00 0.1 °C Temperature difference from 22 °C.
If external temperature is 32 °C
)00?
Returns:
+10.0
Line
Frequency
01 0.1 Hz Line Frequency.
If the line frequency is 60 Hz:
)01?
Returns:
+60.0
Alarm Status 02
Bit 0 – Minimum Temperature Alarm.
Definition for Status Register
Bit 1 – Maximum Temperature
Alarm.
Bit 2 – Minimum Frequency Alarm.
Bit 3 – Maximum Frequency Alarm.
Bit 4 - SAG Voltage Alarm.
Bit 5 – MINVA – under minimum
voltage on VA input.
Bit 6 – MAXVA – over maximum
voltage on VA input.
Bit 7 – MAXIA_NB – maximum
narrowband current exceeded on
Outlet 1.
Bit 8 – MAXIA_WB – maximum
wideband current exceeded on
Outlet 1.
Bit 9 – PFA_NB negative –
Narrowband Power Factor Negative
Threshold Alarm for Outlet 1.
Bit 10 – PFA_NB positive –
Narrowband Power Factor Positive
Threshold Alarm for Outlet 1.
Bit 11 – PFA_WB negative -
Wideband Power Factor Negative
Threshold Alarm for Outlet 1.
Alarms become “1” when
thresholds exceeded.
Note: Additional Status Alert is
Located at addr 0xBD
(see Table 8 )
Note: When AC voltage input is
less than or equal to 10 V
RMS
,
•
Only MINVA alarm is active.
•
All measurements are
forced to 0 except power
factor, which is forced to 1.
Note: The frequency
measurement is forced to 0 as
long as the SAG voltage alarm
is active.