Thermo Scientific DCT6088, User Manual

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Primary Displays & Menus
The Relays Menus
Note The output for the PULSE selections is limited to one cycle per
second. The pulse duration (relay ON time) is approximately 500
milliseconds. If the totalizer increments more than once per second, the
flowmeter tracks how far behind the relay pulses are. The flowmeter
then “catches up” when a flow condition occurs where the totalizer
increments at a rate of less than once per second. To prevent the relay
pulse output from falling behind, the Totalizer Multiplier menu (37)
should be selected so that at the maximum anticipated flow rate, the
totalizer increments once per second or less. For example, if the
totalizer unit is gallons and the maximum anticipated flow is 600
gallons per minute (10 gallons per second), a multiplier of 10 should be
selected.
▲
Note The net totalizer can either increment or decrement depending
upon the direction of the flow. Since the external totalizer (driven by
the net totalizer pulse) can only increment, the flowmeter stops
transmitting pulses whenever negative flow is being measured. The
flowmeter tracks the negative flow and does not start sending pulses to
the external totalizer until the measured negative flow is canceled out
by positive flow. If an application has negative flow for extended
periods of time, separate external totalizers should be used, driven by
the positive and negative totalizers. The net flow total can then be
determined by subtracting the value for the negative external totalizer
from the value for the positive external totalizer.
▲
4. Press the down arrow , and the Relay On Condition Value screen is
displayed. Enter the value for the relay ON condition. Press Enter .
Figure 5–54. Relay On Condition screen
Note
The flow units used for the relays are the same as the flow units
selected for measuring flow in the Flow Units menu (30). ▲
5-22 DCT6088 User Guide Thermo Fisher Scientific