Endress+Hauser RIA452 Betriebsanleitung Seite 93

RIA452
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Endress+Hauser
Simple preset counter
Fig. 22: Simple preset counter
If the preset counter is activated, limit values 1 and 2 are permanently assigned to the preset counter
function (output 1 = main switchoff, output 2 = preliminary switchoff). Digital input 1 is perma-
nently assigned to the "Restart preset counter" function.
Thus, the number of free inputs and outputs available is reduced accordingly. The operating menus
for these inputs/outputs are then hidden.
Set count B (LV B) defines the preliminary switchoff, Set count A (LV A) defines the main
switchoff. Limit value (or start value, see "Pre-counter" function on Page 89) for LV A and prelimi-
nary alarm value for LV B are freely configurable
The positive counting direction is defined as follows: starting at the fixed starting value of zero,
count up until the set limit value is reached (Set count A).
The negative counting direction is defined as follows: starting at the configurable starting value (Set
count A), count down until the fixed limit value of zero is reached.
The counter is reset by means of digital input 1 (Digital Inp.1). Edge Digital Inp.1: Low-High =
start counter.
Calculation formula for flow measurement
If you selected "Formula" under Calc. flow for flow measurement, the flow is calculated using the
following formula:
Where:
3
• Q: Flow rate in m /h
• C: Scaling constant
• h: Headwater level
• , : Flow exponent
• : Weighting factor
Note!
The scaling constant C must always refer to Q in m
in another flow unit.
Examples:
• Q in l/h with C = 2.11
3
1 l/h = 0.001 m /h
C = 2.11 * 0.001 = 0.00211
• Q in USKgal/s with C = 0.35
1 USKgal/s = 13627.4444 m
C = 0.35 * 13627.4444 = 4769.60554
A table with values for converting the various flow units to m
3
/h, i.e. C has to be converted if C is available
3
/h
Commissioning
3
/h is provided in the appendix.
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