ENGLISH
13
Example with CL chlorine with range 2 Cl ppm:
if the selected setpoint is 1 Cl ppm and hysteresis is set at 0.050 Cl ppm, the two activation
values are 0.95 and 1.05 Cl ppm; within this range, the setpoint is OFF and outputs are blocked, outside this range the setpoint is ON (always
according to Direct or Reverse mode).
ADVANTAGES: assuring proper system control without straining the connected device.
DISADVANTAGES: the user must remember that the programmed hysteresis is slightly different from the required setpoint.
D E LA Y output response del ay on set poi nt
The Delay time
blocks the output relays (max 999 sec. programmable) to ensure the outputs are active only when the sensor
measurements are stable, thus assuring the best results in terms of chemical balance.
P R O P O R TIO N A L -
PWM mode: Timed “Pulse Width Modulation”
PWM
“pulse width modulation” supports a proportional mode
on each setpoint activating at the pulse, with a change of the
Start/Stop cycle time according to the measured value
with respect to the setpoint.
Pulse width:
pulses are timed ON and OFF based on the distance from the selected setpoint, programmable, example: if the
selected setpoint is 0.500 Cl ppm and the measured value is 0.400 Cl ppm, if the selected value of the PWM
mode is 0.050 Cl ppm (based
on the selected range) the proportional function starts after reaching 0.450 Cl ppm with Time/Pause pulses and decreasing the active time
while reaching the setpoint.
Cycle Time:
selected value of the
PWM
mode 0.050 Cl ppm with a 60 second cycle (programmable), example: setpoint is 0.500 Cl
ppm active time 60 sec - pause time = 0 sec; at 0.450 Cl ppm active time = 30 sec -
pause time = 30 sec… decreasing the active time while
reaching the setpoint. The cycle time depends on many variables, such as: distance from the injection point of the system to be treated, how
fast or slowly the setpoint needs to react, chemical concentration, etc.
MIN Active Time:
programmable. Defines the minimum time in which the PWM function is active; prevails over the selected
settings. The pulse modulation function is adjusted with 3 functions according to the following formula: Active T ime in accordance with the
selected formula = (measured value - setpoint) / (period width * cycle time). If the result of the formula is < than that chosen with MIN
Active Time, the latter prevails on the former, example: range 2 Cl ppm measured value 0.400 Cl ppm; setpoint 0.500 Cl ppm / Period
Width 0.050 * Cycle time 60 sec = active time 4 sec. If the user has selected Active time min 5 sec, this will be the minimum PWM time
and not 4 sec.
ADVANTAGES: the proportional function is more accurate than the ON-OFF mode.
DISADVANTAGES: to select the most accurate settings and assure the best results, the operator should be an expert.
A N A LO G U E O U TP U TS I N C U R R E N T 4 -20 m A 1 / 4 -20 m A 2
The instrument features 2 outputs with signal in current in mA. The 4-20mA1 and 4-20mA2 signal follows the Chlorine settings
selected previously. The mA output provides two operating modes to be selected according to the system’s operational requirem
ents:
mA DEVICE:
this is a programmable function combined with the unit of measure of the Chlorine in real time which makes it therefore
possible to remotely monitor devices such as data loggers, PLCs, recorders or other devices suited to processing remote signals in mA.
4
mA
corresponds to the minimum Chlorine value (0 Cl ppm),
20 mA
corresponds to the maximum measurable value (according to the
selected chlorine range) which may be 2, 20, 200 or 10 Cl ppm, the connected device is activated accordingly.
METERING ON SETPOINT:
the mA outputs control metering pumps suited to processing an mA signal on input. 4 mA corresponds
to the minimum Chlorine value (0 Cl ppm), therefore the connected metering pump operates at the minimum capacity. 20 mA corresponds to
the maximum measured value (according to the selected chlorine range) which may be 2, 20 or 10 Cl ppm, the connected metering pump
will work at the max programmed capacity (according to the settings of the device).
ADVANTAGES: best possible results because the pulses are extremely accurate in relation to measured levels.
DISADVANTAGES: the user requires a specific metering pump or other device suited to processing an input signal in mA.
O V E R D O S E TI M E
With the
overdose time
alarm one can select a period during which the setpoint must be reached. If the setpoint is not reached
during this period of time, the instrument blocks output operations, including those in mA (metering pumps), the alarm is ON (displayed) and
triggers a relay output.
ADVANTAGES: preventing excessive doses of chemicals.
M A X I M UM M E TE R I NG TIM E
The
maximum metering time
is an extra function that ensures that metering operations are completed within a certain time
limit selected by the operator. The relays connected to the metering pumps activate accordingly. This function makes it possible to
eliminate time limits, to meter continuously based on the selected setpoints or, if the operator wishes to change the settings, it lets them
choose a given period (up to 999 minutes) within the selected hours.
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