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8.5 “PWM” (fixed), pH
This mode is valid for “pH relay” and “pH relay 2” outputs only.
Pulse-width modulation (PWM) of a signal or power
source involves the modulation of its duty cycle, to either convey information over a communications channel or
control the amount of power sent to a load. Using fixed mode is possible to set operating time to switch on or off
selected output.
During this time if reading value will move towards a set value (on or off) the PWM will operate the output on
timered basis. Reaching the set value the PWM will permanently leave on (for selected amount of time) or off the
output.
Parameters to set for this mode are:
pH range: two pH values within PWM operates.
Ton: ON period, during output activity.
Toff: OFF period, during output activity.
For example: set first pH value (OFF) at 7.20.. Set second pH value (ON) at 8.00.
Set “working-pause” output activity with Toff 0 seconds and Ton 40 seconds.
For reading values
≥
to 8.00 the output will be ON with activity based on Ton and Toff.
For reading values
≤
7.20 the output will be permanently OFF.
For reading values within working range operating mode is on HYSTERESIS base. Once reading value is 7.20 pH will be permanently off until it will
reaches 8.00 pH.
7.20
8.00
ON
OFF
Ton: 40 seconds WORK
Toff: 10 seconds PAUSE
