79
Percent On
Number of Relays
Relay
2
3
4
5
6
1
60.0%
47.4%
41.5%
38.4%
36.5%
2
40.0%
31.6%
27.7%
25.6%
24.4%
3
21.1%
18.5%
17.1%
16.2%
4
12.3%
11.4%
10.8%
5
7.6%
7.2%
6
4.8%
Output Activation Modes
Depending on the current control mode selection for the Lead output, additional settings may be available within
the settings list of the last output in the group to provide additional option(s) to optimize the behavior of the Lead
Lag functionality. Several different activation modes can be selected to control the status of additional output(s)
based on either elapsed time, alternate setpoints, and/or alternate switch inputs.
Disabled
No action is taken to activate more than one output within the Lead Lag group of outputs. This mode is used when
a group of Lead Lag outputs exists only to provide backup in case of a Flow Verify failure on one of the pumps, or
if a pump is taken out of service, and/or if only wear leveling is desired.
Time Based
Lag outputs are activated following the Lead output after a user-settable delay. The same delay value is used for
all outputs. This menu selection is available only when the Lead output is using On/Off, Dual Setpoint, Spike or
Manual control modes.
Example: If the Lead output is set to Manual, this control option could be used to force on the output based on a
digital input signal (e.g., level switch). If the level switch remains open for more than the specified delay time, the
second output in the Lead Lag group is energized. If another delay time elapses, a third output (if available) is also
turned on.
In On/Off, Dual Setpoint, or Spike control modes, additional pump(s) are energized if the process value remains
outside the setpoint range for more than the specified delay time.
Example: In a two-output Lead Lag group (R1←R2), the Lead (R1) output, set for Dual Setpoint control, is pro
-
grammed to energize its output when the D.O. reading is outside the 4.0-4.5 ppb control range with a deadband of
0.1 ppb. Time based output activation is selected with a delay time of 15 minutes. When the D.O. value falls below
4.0 ppb, R1 is activated. After 15 minutes, if the D.O. has not risen to 4.1 ppb or higher, R2 will also be activated.
When the process value reaches 4.1 ppb, both outputs are turned off.
Setpoint Based
Each Lag output has its own setpoint(s) and deadband when this option is selected. The setpoints for each output
in the Lead Lag group are evaluated individually and outputs are added as needed based on the current process
value. Setpoint based activation mode also incorporates time based activation and can also be configured to trigger
an additional pump (if available) after a specified delay time. This menu selection is available only when the Lead
output is using On/Off or Dual Setpoint control modes.
Example 1: The Lead output (R1) is set for On/Off control of pH with a setpoint of 8.50, a deadband of 0.20 and
a “force lower” control direction. The first Lag output (R2) has a setpoint of 9.00 and a deadband of 0.20. The
second Lag output (R3) has a setpoint of 9.50 and a deadband of 0.20. The delay time is disabled (set for 0:00 min
-
utes). Wear leveling is disabled. When the pH goes above 8.50, R1 energizes. If the pH proceeds to exceed 9.00, R2
energizes. And if the pH rises above 9.50, R3 energizes. When the pH decreases to below 9.30, R3 goes off. When
the pH falls to below 8.80, R2 goes off. And finally, when the pH decreases to below 8.30, R1 is turned off.
Example 2: The same three-pump configuration (R1←R2←R3) as in Example 1 except the delay time is set for 30
minutes. When the pH goes above 8.50, R1 energizes. If 30 minutes passes before the pH exceeds 9.00 or drops
below 8.30, R1 remains on and R2 is energized. If the pH then rises above 9.00, the next output in the group, R3, is
