LTH Electronics MTD75, Operation Manual

Page: 81 / 266

Inhibitor
MTD75 Operation Guide - 79 -
Inh
ibitor
Inhibitor Control Functions
The Inhibitor menu contains the basic configurations for the Inhibitor output. The user can select to
initiate the Inhibitor dose in a number of ways by selecting the appropriate trigger condition at the
“Source” menu item. Selecting “Off” from the “Source” menu item can permanently deactivate the
Inhibitor relay output.
Dosing By Volume
When the “Source” menu item is set to “Volume” the MTD75 will count the volume of water given from
the ‘K’ factor (see page 151) and the water meter input (see page 52). After the amount equals or
exceeds the level set the Inhibitor relay will activate for the dose duration. The volume of water passed
since the last dose and the amount of water remaining to the next dose are displayed on the front
screen (see page 55).
Timed Dosing
When the “Source” menu item is set to “Time” the MTD75 will initiate the Inhibitor dose after the
selected period. The user must first select the overall period of the dosing cycle (i.e. per
week/day/hour). From there the user can then select the interval of dosing.
When the Dose cycle (“Dose Per”) is set to “Hour” the user can then select the interval between doses
to the minutes and seconds. When the dose cycle is set to “Day” the interval can be set to the hours
and minutes.
When the Dose cycle is set to “Week” the user can select which days of the week the dose occurs on,
the time of day that dose occurs and its duration. Both the time of day and the duration can be set
different for each day of the week.
If the trigger source is “Volume” then the controller also offers a background “Timed Dose”. When
enabled the timed dosing menus will also appear, working the same way except when the cycle is set
to “Week”. When this occurs the user will be able to select an interval from 1 to 6 days.
Dosing By Bleed Duration
The MTD75 includes the facility to dose the Inhibitor in proportion to the amount of bleed time that
has accumulated. Selecting the “Bleed” trigger in the “Source” menu and setting the time accordingly
at the “Bleed Time” menu item can simply do this.
Dosing From The Water Meter
The MTD75 provides the facility to generate a pulsed output directly in proportion to the water meter
input. When the trigger is set to “xMeter” the controller will output a set number of pulses for every
input pulse received. When set to “÷Meter” the controller will require a set number of input pulses for
one output pulse.
Output Configuration
Depending on the trigger selected the relay output can be configured to operate as an “On/Off”
output or a “Pulse” output. In either case the duration of the dose is set in the “Dose Duration” menu
item.
When the output is set to “Pulse” the user can select the “Stroke Rate” which is the frequency of the
output pulses. The output pulse width is fixed at 0.2 seconds.