Logic Examples - MultiTrode MultiSmart Installation & Operation Manual

MultiSmart Installation & Operation Manual

25.6 Logic Examples

Some examples of logic expressions are shown below:
25.6.1 Example 1: Changing the Lead (Duty) Pump Setpoint from an Analog Input
This example allows the Lead (Duty) pump to have its activation setpoint changed via an analog input.
The left side of the expression above represents the activation setpoint for the lead pump.
•
The right side of the expression is AIN1 on the top board multiplied by a factor of 4. So if AIN1 is
•
15mA, the lead (duty) pump setpoint will be 60%.
PumpControl.Behaviour._1.ActSetPoint =
valueof("IO.Unit._1.TopBoard.Ain._1.Value")*4
NOTE: A "Behaviour" is the name used internally for lead/lag pumps. In alternation mode, the
setpoints aren't assigned to physical pumps but rather to their position in the cycle.
25.6.2 Example 2: Start the Station if an Analog Input Falls below a Certain Value
The MultiSmart includes a station function called Pulse Start. This was originally designed so that a Digital
Input, when closed or opened, could start one or more pumps. See Section 16.2.3 for a description of this
feature.
In this example, a logic engine tag is set to trigger the pulse start instead of "ValueDigital". A logic file is then
used to define when this feature is activated. Rather than just activating in response to the digital input, this
example uses an analog input to trigger the digital input when it passes a set value.
Logic.Values.Digital01 = valueof("IO.Unit._1.TopBoard.Ain._2.Value") < 12
What this does is test if AIN2 in the top board of I/O unit 1 is less than 12mA. This Boolean expression
resolves to 0 if AIN2 >=12mA, and resolves to 1 if AIN2 <12mA. As a result, the virtual Digital Input01 gets
set to 1 or 0.
When it changes from 0 to 1, i.e. when AIN2 falls below 12mA each time, the station operates its pulse start
functionality.
25.6.3 Example 3: Change Pump Mode if an Analog Input Falls Below a Set Value
PumpControl.Pump._1.PumpMode = 2 *
(valueof("IO.Unit._1.TopBoard.Ain._2.Value") < 7)
If AIN2 is below 7mA, the value of the expression on the right =2. This value for pump mode puts the pump
into semi-automatic manual (i.e., manual until the pump reaches its deactivation setpoint, at which time it
reverts to auto mode).
If AIN2 is above 7mA the value of the expression on the right =0. This puts the pump into Auto mode. The
above expression could also be achieved by the following:
PumpControl.Pump._1.PumpMode = if
(valueof("IO.Unit._1.TopBoard.Ain._2.Value") < 7, 2, 0)
MultiSmart_IO_Manual_A4_v2-22_R15.doc Page 179 of 201