Examples and Best Practices for the CODESYS Trace Scripting API

In the following code snippet, a variable with the specified name is first found and then removed from the ScriptTraceVariableList.

def remove_variable_by_name(traceObject, variableName):
        index_to_remove = -1
        for variable in traceObject.variable_list:
                if variable.variable_name == variableName:
                        index_to_remove = traceObject.variable_list.index_of(variable)
                        break
        if index_to_remove != -1:
        traceObject.variable_list.remove(index_to_remove)    

The following code snippet is based on the "Creating a Trace" snippet.

traceObject.resolution = Resolution.MicroSeconds

Use Resolution.MilliSeconds if you want recording based on milliseconds.

The following code snippet is based on the "Creating a Trace" snippet.

traceObject.record_condition = "PLC_PRG.bDoRecord"

The following code snippet is based on the "Creating a Trace" snippet.

traceObject.comment = "This trace records the ..."

The following code snippet is based on the "Creating a Trace" snippet.

traceObject.auto_start = True

The following code snippet is based on the "Creating a Trace" snippet.

traceObject.every_n_cycles = 10

The following script is an example for creating a simple diagram where all variables are used.

First, a ScriptTrace object and some ScriptTrace variables are created.

traceObject = projects.primary.find("Device","PLC Logic","Application","Trace")[0]
assert traceObject.is_trace_object
for i in range(5):
        traceObject.add_trace_variable(variableName="PLC_PRG.a"+str(i))

Next, a ScriptTrace diagram is created and then all ScriptTrace variables are added.

traceDiagram = traceObject.diagrams.add()
for traceVar in traceObject.variable_list:
    traceDiagram.add_diagram_variable(traceVar)

The following Python method takes one ScriptTrace object and adds a diagram per ScriptTrace variable.

def one_diagram_per_variable(traceObject):
    assert traceObject.is_trace_object
    for traceVar in traceObject.variable_list:
        diagram = traceObject.diagrams.add(traceVar)
        diagram.name = traceVar.variable_name

The following code snippet finds the Trace trace of the Application application, downloads it, and starts it.

proj = projects.open(r"<Path to the project file>")
app = proj.find("Device", "PLC Logic", "Application")[0]
with online.create_online_application(app) as onlineapp:
    traceObject = proj.find("Device", "PLC Logic", "Application", "Trace")[0]
    onlineapp.login(OnlineChangeOption.Never, True)
    onlineapp.start()
    editor = traceObject.open_editor()
    editor.download()
    editor.start()

The following code snippet is based on the "Downloading and starting Trace" snippet.

A trace must be stopped before it can be saved. This can be done either by reaching the trigger condition or by an explicit call of stop().

It is assumed that a trace is already running.

editor.stop()
editor.save(r"<File path to csv file>")

The following code snippet is based on the "Downloading and starting Trace" snippet.

It is assumed that a trace is already running.

print("Packet State: {}".format(editor.get_packet_state()))
print("Trace started at {} (absolute timestamp)".format(editor.get_trace_start_timetamp()))

traceObject = proj.find("Device", "PLC Logic", "Application", "Trace")[0]
traceObject.trigger_variable = "PLC_PRG.bVar"
traceObject.trigger_edge = TriggerEdge.Positive
traceObject.post_trigger_samples = 20

The trigger level is required only for numeric trigger variables. However, it is good coding style to explicitly set the trigger to None.

traceObject.trigger_level = None

traceObject = proj.find("Device", "PLC Logic", "Application", "Trace")[0]
traceObject.trigger_variable = "PLC_PRG.iTemperature"
traceObject.trigger_edge = TriggerEdge.Positive
traceObject.post_trigger_samples = 20

If the trigger variable is of type REAL or LREAL, then the trigger level can also be specified as a floating-point number (for example, 80.5).

traceObject.trigger_level = 80

The following code snippet is based on the "Downloading and starting Trace" snippet and "Configuring a * trigger".

triggerstate = editor.get_trigger_state()
while triggerstate != TriggerState.TriggerReached:
        system.delay(200)
        triggerstate = editor.get_trigger_state()

editor.save(r"<File path to csv file>")

The following code snippet is based on the "Downloading and starting Trace" snippet and "Configuring a * trigger".

print("Trigger reached at {} (absolute timestamp)".format(editor.get_trigger_timetamp()))
print("Trigger reached at {}".format(editor.get_trigger_startdate()))
print("Trace was running {}ms until trigger has been reached".format(editor.get_trigger_timetamp() - editor.get_trace_start_timetamp()))

The following code snippet is based on the "Downloading and starting Trace" snippet and "Configuring a * trigger".

editor.reset_trigger()

myDevice = projects.primary.find("Device")[0]
devicetrace = trace.create(myDevice, "DeviceTrace")

The following code snippet is based on the "Creating a DeviceTrace" snippet.

traceObject = projects.primary.find("Device", "DeviceTrace")[0]

For application traces, the result of get_online_traces contains only traces of the application.

# traceObject = projects.primary.find("Device", "PLC Logic", "Application", "Trace")[0]
editor = traceObject.open_editor()
for tracepacket in editor.get_online_traces():
    print(tracepacket)

The following code snippet is based on the "Creating a DeviceTrace" snippet.

traceObject = projects.primary.find("Device", "DeviceTrace")[0]
editor = traceObject.open_editor()
editor.upload_to_device_trace("CpuCoreLoad")