5.3.2 Unit Test Methodology
Like creation of control application, unit test should be carried out in a bottom-up
manner, starting from the smaller logic parts and combining them into larger parts.
This section describes this method using the control application example described
below.
Application Example: Reaction Tank Heating Application
This sample heating application consists of several parts as described below, with
multiple reaction tanks using the same heating application.
- Control loops
NPAS_PID (tag name TIC001) for temperature control
NPAS_PG_L30 (tag name TIC001PG) for heating program setup
- Conditional logics
Conditional logic for starting heating
Conditional logic for ending heating and logic for transiting to constant state
Logic for stopping and restarting heating
- User function blocks
As the above conditional logics are used in multiple places, they are registered
as user function blocks.
START : Conditional logic for starting heating
END : Conditional logic for ending heating and logic for transiting to constant
state
STOP : Logic for stopping heating
The figure below shows the schematic of the application example.
Temperature
control PID�
TIC001
Heating application
Control loops
Heating
program setup
TIC001PG
Logic for
starting heating
START
Logic for
ending heating
END
Logic for
stopping heating
STOP
Conditional logics
In this example, the basic control involves two main control loops, named TIC001
and TIC001PG, which are activated and deactivated by conditional logic.
The conditional logic cannot be tested unless the control loops operate correctly. So,
first debug the control loops.
Next, debug the user function blocks. At this stage, debug the logic of each user
function block by itself, without considering the operation of the control loops.
To Next Page
Loading...
Need help?
General
