Pulse
Generator
Pulse
Interface
PCPW
protected
access
PGPW
protected
access
TPPW
protected
access
Pulse
Counter
Plain measurement
software block
- Accesses sensors
- Calculates consumption
- Unlocks MRIF with “PGPW”
- Sends “legal relevant data”
as pulse count to MTIF
Setup (after reset)
Calibration request
Inspection request using TPPW
Plain accounting software
- Receives “legal relevant
data” as pulse counts using
“PCPW”
- Maintains redundancy
statistics and other data
(for example, daily, weekly,
monthly, yearly consumption)
Scheduler or operating system (trustworthy, certified, real time)
- Provides sufficient software separation to satisfy WELMEC and others
- Low-power mode cycling (LPM0, LPM1, LPM2, LPM3, LPM3.5)
- Manages time-controlled execution and exception handling
For example, invoked
once per second
For example, invoked
once per second
Invoked on activation
Invoked on request
(Field) Inspection device
Calibration device
or manufacturer test bench
MTIF Introduction
620
SLAU367P – October 2012 – Revised April 2020
Copyright © 2012–2020, Texas Instruments Incorporated
Metering Test Interface (MTIF)
23.1 MTIF Introduction
The Metering Test Interface (MTIF) is module is used to implement a simple pulse interface indicating the
current consumption measured by the meter. MTIF provides three independent password-controlled
access ports. One for the pulse generator, one for the pulse counter, and one for configuration and
maintenance. Because all three passwords are different, a clear software separation can be achieved.
shows an assumed software stack of a meter that is divided into smaller blocks, thus allowing
certification. The measurement software block measures the consumption and delivers its values to the
MTIF pulse generator. The accounting software picks up the pulses from the pulse counter and generates
the consumption values and records them. During a field inspection or calibration, the MTIF pulses are
brought out to the MTIF output pins without changing the operation mode of measurement software and
accounting software. A scheduler or operating system can invoke measurement software and accounting
software at independent rates. The pulses on the MTIF output pin are generated in the power modes AM,
LPM0, LPM1, LPM2, LPM3 and LPM3.5.
Figure 23-1. MTIF Use Case
shows the MTIF in its operation. At t = 0 seconds, a consumption of 5 units is measured, this
consumption increases stepwise, first to 7 units then to 17 units per second. The single measurement
values are converted into pulses by the pulse generator, then transferred to and counted by the pulse
counter. While the MTIF output is enabled, the pulse train is sent to the MTIF output.