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Hysteresis
Each limit value output reacts only after the 1
st
, 2
nd
or 3
rd
bad analysis result has been detected (suppression of the first
or the second measured value).
This increases the reliability during the evaluation of the analysis e. g. after the measuring point has been switched over
or if the sampling line has possibly not been flushed sufficiently. The hystereses of the two outputs LV1 and LV2 can
be set independently from each other.
Operation: With a hysteresis of 2 a further analysis is carried out immediately after the limit value has been exceeded.
Only if the limit value of this analysis is exceeded again, the corresponding output is energised. If you have set a
hysteresis of 3, the corresponding output reacts only after the limit value has been exceeded for the 3
rd
time in
succession.
Logic functions of the limit value outputs LV1 and LV2
Logic function 0, Duration
Output relay LV1 or LV2 pulls up when the measured value rises above limit value LV1 or LV2. If the measured value
falls below the limit value LV1 or LV2 the relevant relay drops out again.
Logic function 1, Impulse
If the measured value rises above limit value LV1 or LV2, the relevant output pulls up for a set time t. Independent of the
time taken for the limit value to rise above the set limit, the relevant output always remains in the "ON" position for the
set time.
Logic function 2, Interval
If the measured value rises above one limit value, the relevant output pulls up at intervals with the time
set.(Impulse/Pause)
Logic function 3, Two-point
If the upper limit value LV1 is exceeded, the output relay LV1 pulls up. If the lower limit value LV2 falls below the set
limit, output relay LV1 drops out.
The output relay LV2 pulls up according to the programmed logic function.
L This function is possible only if different values are selected for LV1 and LV2. For
example for LV1 =0.2° dH and for LV2 =0.1° dH.
BOB-Operation (BOB = Operation without constant supervision)
The Testomat ECO conforms to the german TRD 604 safety standard for monitoring of water hardness associated with
steam boiler installations, when operation without constant supervision is a relevant safety feature (= Betrieb Ohne
ständige Beaufsichtigung = BOB -operation).
When the BOB function is programmed, the unit constantly monitors the reagent quantity available. For calculating the
reagent consumption per analysis, a measured value of 1.48 ppm CaCO
3
(0.015 mmol/l alkaline earth ions) is used. An
alarm is activated if the residual reagent quantity is insufficient for the set BOB period of 72 hours.
BOB on: Continuous monitoring of the residual reagent quantity. ALARM message when the available quantity falls
below the minimum quantity for the BOB period: “Alarm“ flashes, the Alarm output is energised.
BOB off: Without BOB function: the residual reagent quantity is only monitored for the minimum quantity (10 %
level).
Example: BOB-Duration = 72 Hours Number of analyses per hour = 10
Necessary quantity of reagent for 72 h = 72 h x 10 Analysis/h x (3 x 30) µl/Analysis = 64.8 ml.
(That corresponds to approx. 13% of a full level bottle)
Funktion STOP
The active analysis interval can be interrupted through contact with the stop input. The active condition has to be
programmed according to your requirements.
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