Instruction Manual
Tek-LCD 7801C
www.tek-trol.com
Technology Solutions
67
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Alternation Input Sources
Most level control applications use channels as the input. The channel is setup to read the signal
from a level transmitter and display the level either in height or volume units. The continuous
level monitoring allows for selecting multiple alternation points.
If the input is other than a channel, the alternation is limited to only one pump on at one time.
A level switch could be connected to a digital input and the digital input will alternate the pumps
for each on/off cycle.
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Set (On) & Reset (Off) Points
Up to eight alternation points can be entered to alternate eight relays per group. The On & Off
points determine if pumps are on when the level rises or when it falls.
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On & Off Time Delays
To prevent turning pumps off and on at the same time, it’s recommended to use On delays. The
On & Off delays are common to all the relays in the alternation group.
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Alternation Groups
An alternation group is made up of a primary relay and any number of relays selected to
alternate with it. Multiple alternation groups can be setup using different sources for each
group. A relay should NOT be assigned to more than one group.
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Alternate on Time
This is the maxim
um time any relay in the group will be continuously on. After the alternation
time has elapsed, the relay will turn off and another relay will turn on. This feature is useful for
applications where the level is maintained with one pump for a long time. Depending of the
setup and conditions, it will help distribute the load among the pumps in the group.
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Break
If Relay On is selected, only one of the alternation relays will be on when a break is detected*.
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Alternation Sequence
The first relay on is the first relay off, when more than one relay are activated. The lowest reset
point (Off) is used for the alternation cycle.
*Note: Break needs to be set in the analog input menu.
6.50
Setup Digital Output
The Digital Output menu allows assigning the 4 outputs to various events generated by digital
inputs, On/Off channels, alarms, and horn on state.
o
Edit the digital output tag
o
Select the input
o
Select the Break condition
o
Invert Output logic
