Etatron eSelectM 2 PH-CL Operatinginstructions And Maintenance Download Page 29

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MIN Active Time:

programmable. Defines the minimum time for which PWM is active; prevails over the selected

settings. The pulse modulation function is adjusted with 3 functions according to the following formula: Active
Time in accordance with the selected formula = (measured value - setpoint) / (period width * cycle time). If the
result of the formula is

of that selected with MIN Active Time, the latter prevails on the former.

PWM PROPORTIONAL MODE FOR RX WITH TIMED PULSES

Window width:

pulses are timed ON and OFF based on the distance from the selected setpoint

(programmable). Example: if the selected setpoint is 750 mV and the measured value is 500 mV, the

PWM

mode starts after reaching 550 mV with Time/Pause pulses and decreasing the active time while reaching the
setpoint.

Cycle Duration:

the PWM mode has a 60 second cycle (programmable), example: setpoint is 700 mV, the

measured value is 550 mV = active time 60 sec - pause time = 0 sec; at 625 mV active time = 30 sec - pause
time = 30 sec… as a consequence the active time decreases 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 for which PWM is active; prevails over the

selected settings. The pulse modulation function is adjusted with 3 functions according to the following formula:
Active Time in accordance with the selected formula = (measured value - setpoint) / (period width * cycle time).
If the result of the formula is

of that selected with MIN Active Time, the latter prevails on the former.

BY SELECTING

“ON-OFF”

THE NEXT PROGRAMMING STEPS ARE AS FOLLOWS

……

FUNCTION NOT AVAILABLE WITH PROPORTIONAL MODE

Hysteresis

is useful during operations to adjust the setpoints in ON-OFF

mode and is used to enable or disable the output relay when the selected
hysteresis has been achieved. Hysteresis is useful when there are too many
quick swings around the setpoint, that might damage the connected device.

FUNCTION NOT AVAILABLE WITH PROPORTIONAL MODE

The Delay time

blocks the output relays (max 999 sec. programmable) to ensure the outputs are active only

when measurements are stable, thus assuring the best results in terms of chemical balance.

GOING BACK TO THE SETPOINT PROGRAMMING STEPS FROM THE

“ON-OFF”

MODE OR

“PROPORTIONAL”

MODE

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 displayed as ON and triggers a signalling instrument if it is connected to the
alarm relay.

Maximum Metering

is an extra safety function that ensures metering is

completed in the selected time. This function makes it possible to eliminate
time limits (continuous metering according to the selected setpoints) or to
select the minutes (up to 999) and the hours, for instance metering for 999
minutes in 24 hours.

ONLY WHEN USING METERING PUMPS

The priming function blocks the setpoint value to allow the metering pump to
remain primed.

Press E S C to go back to

M E N U S E L E C T I O N

or press E S C

E S C to go back to

M E A S U R E M E N T D I S P L A Y

MENU SETPOINT 2 (pH)

Min.Active Time

5 s ec

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