Metrima SVM F2, User Manual

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15
5 Verifying the calculator
Verification of the calculator's measurement accuracy is undertaken in the test mode, where the
energy value/flow sensor pulse is issued via the HF-output at the service adapter. For each flow
sensor pulse, measurement takes place on the temperature sensors and a pulse burst
corresponding to the measured energy of the meter is issued.
To test (verify) the measurement accuracy of the calculator by means of HF-pulses proceed as
follows:
1. While short circuiting the test button with a “Test key”, see fig. 4.1a and 4.1b, hold the “Push
button” until the display mode changes.
2. The calculator now enters test mode. This is indicated by a flash symbol being displayed.
3. Connect fixed resistance for simulation of Pt100 via terminal block units Nos. 5-6 (flow) and
7-8 (return).
4. Connect a pulse generator via terminal block unit Nos. 10-11 (connection 11 is ground) in
order to simulate flow sensor pulses. Note: Voltage level is max. 3V.
5. Connect an OPTO-head/interface with HF-pulse interface at the front.
6. Simulate a flow sensor pulse after which the meter issues an (approximately) 20 kHz pulse
burst corresponding to 100*k*dt pulses via the HF-output. “k” is the energy factor.
(kWh/°C/m3) and dt is the difference between simulated flow and return temperatures.
Example: Rf=138.50 (100.00°C), Rr=127.07 (70.00°C) => dt=30.00°C, k=1.141 gives
100*1.141*30 = 3423 pulses
7. The next flow sensor pulse can be sent immediately after the HF-pulse burst from the meter
has been dispatched.
To leave test mode proceed as follows:
1. While short circuiting the test button hold the “Display Button”, see fig.1.1b.
2. The calculator now enters operation mode.
To verify (test) the measurement accuracy of the meter with help of the display, first set up
connections in accordance with points 3 and 4 above for testing by means of HF-pulses. Testing
is undertaken in the meter's operation mode. Proceed as follows:
1. Supply flow sensor pulses until the energy display is incremented one step.
2. Supply flow sensor pulses with a maximum frequency of 12 Hz until the display has been
stepped appropriate numbers of steps.
3. Errors in testing decrease with the number of steps made during the test. If the meter is
programmed for 1.0 litre/pulse and resolution for display of energy is 0.001MWh, this means
that 10 steps on the display correspond to 288.85 pulses from the flow sensor with selected
temperatures in accordance with the above. The testing error is m - 1 pulse, which,
in the example, corresponds to 0.35%.