Hanna Instruments Groline HI981413, Инструкция по эксплуатации

Страница: 24 / 48

24
SETUP
Measurement Mode
Option: Electrolytic Conductivity (EC) or Total Dissolved Solids (tdS)
Measurement units will be mS/cm for EC and ppm for TDS measurements.
Press the arrow keys to switch between the options.
“MEASURE MODE” message is scrolled on the bottom of the LCD screen.
Set point
General: a set point is a threshold value that will trigger control if the measurement value crosses it.
With a Hi control mode, the measurement approaches the set point from a higher measurement value.
With a Lo control mode, the measurement approaches the set point from a lower measurement value
than the set point.
Option: user selectable
Press the arrow keys to assign the set point value.
“SET POINT” message is scrolled on the bottom of the LCD screen.
Note: To enter Set point screen, pump control mode must be set as Auto.
Hysteresis / Proportional Band
Hysteresis (On/Off control only)
On/Off control action turns the dosing On or Off based on a previously assigned set point. The pump
status (running or not running) changes depending on EC changes. To prevent oscillation, an EC band,
called hysteresis, is created between the on and off operations.
The pump starts dosing when the measurement crosses the set point value. The pump stops dosing
when the measurement crosses the set point value ± hysteresis band.
In order to set the hysteresis value, automatic control must be enabled, with On/Off control type On.
Proportional band (Proportional control only)
The proportional band is a control variable and is defined as the amount of change in input, required
to cause the control output to go through 100% of operating range.
In order to set the proportional band value, automatic control must be enabled, with Proportional
control type on. The pump is continuously on at the set point value with added band.