TECHNICAL DESCRIPTION MULTICAL
®
401
5512-091 GB/02.2008/Rev. J1
57
13.2 Auto-integration
When the meter is in testing mode, auto-integration can be started by simultaneously pressing the display
change button and the internal button marked “P” for approx. 0.5 seconds. Auto-integration can also be started
serially through the test plug.
If the function is started manually, the meter automatically carries out an energy calculation corresponding to a
flow quantity of 100 l and 10 energy calculations with the current temperatures.
This test takes approx. 20 sec. Once an auto-integration has been started it cannot be interrupted.
NB: Only possible when pins 7-8 are short-circuited under the verification seal.
13.3 Energy calculation
The “true” energy supplied to a MULTICAL
®
401 during verification must be calculated very accurately as the
”true” energy forms the basis of the meter’s verification deviation.
The energy can be calculated as follows:
EMJ=
m³
x t x k
STUCK
[MJ]
EGJ=
1000
EMJ
[GJ]
EkWh=
6.3
EMJ
[kWh]
EMWh=
3600
EMJ
[MWh]
Table 21
m³ is the water quantity applied (or simulated) during verification.
t is the difference between the flow and return temperatures (tF - tR). No matter whether the verification is carried
out with the sensors in liquid bath or with precision resistors, the temperatures must be entered with great
accuracy.
k
STUCK
is the heat coefficient of the water, which is found in the tables of “Tabellen von Wärmekoeffizienten für
Wasser als Wärmeträgermedium”, issued in 1986 by Wirtschaftverlag NW.
On Kamstrup’s METERTOOL CD a calculation program for the ”true energy” is found under verification.
Please note that before looking up the k-value the following information must be available:
– Flow temperature, t
F
– Return temperature, tR
– Flow sensor position: flow or return pipe
– System pressure (16 bar according to EN 1434)
The k-factor is stated in the table as a basis for energy measurement in MJ and must therefore be converted in
accordance with the above-mentioned formulas, if the energy should be expressed in other measuring units.
NB.: Only passive precision resistors can be used for test and verification of MULTICAL
®
401. An electronic
resistance simulator, e.g. based on a power controlled FET, is not suitable as MULTICAL
®
401’s testing current is
intermittent (bursting).
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