EPICSCAClient

The MARTe2 EPICSCAClient allows triggering messages based on the values of EPICS Channel Access (CA) process variables (PVs).

Warning

The EPICSCAClient is only available in distributions where EPICS Channel Access is installed.

In this example, the EPICSCAClient is used to:

  • Trigger StateMachine transitions based on PV values.

  • Monitor the application status by publishing state updates to EPICS.

EPICSCAClient configuration. PV names are automatically updated by Makefile.cfg.
 1+EPICSCA = {
 2    Class = EPICS::EPICSCAClient
 3    StackSize = 1048576 
 4    CPUs = 0x1 
 5    AutoStart = 0 
 6    +PV_STATUS = {
 7        Class = EPICS::EPICSPV
 8        PVName = XSTR(MARTE2-TUTORIAL-USERNAME-APP-STATUS)
 9        PVType = uint32
10    }
11    +PV_COMMAND = {
12        Class = EPICS::EPICSPV
13        PVName = XSTR(MARTE2-TUTORIAL-USERNAME-APP-COMMAND)
14        PVType = uint32
15        Event = {
16            Destination = StateMachine
17            PVValue = Function
18            FunctionMap = {{"2", "GOTO_WAVEFORM_REF"}, {"1", "GOTO_CONSTANT_REF"}, {"0", "GOTO_SWITCH_OFF"}}
19        }
20    }
21}

The StateMachine is configured to send a message every time the state changes, allowing external systems (via EPICS) to track the application status.

StateMachine configuration highlighting messages sent on state changes (starting from the ENTER substate).
 1+StateMachine = {
 2    Class = StateMachine
 3    +CONSTANT_REF = {
 4        Class = ReferenceContainer
 5        +ENTER = {
 6            Class = ReferenceContainer
 7            +InformStatusUpdate = {
 8                Class = Message
 9                Destination = "EPICSCA.PV_STATUS"
10                Function = CAPut
11                Mode = ExpectsReply
12                +Parameters = {
13                    Class = ConfigurationDatabase
14                    param1 = 1
15                }
16            }
17        }
18    +WAVEFORM_REF = {
19        Class = ReferenceContainer
20        +ENTER = {
21            Class = ReferenceContainer
22            +InformStatusUpdate = {
23                Class = Message
24                Destination = "EPICSCA.PV_STATUS"
25                Function = CAPut
26                Mode = ExpectsReply
27                +Parameters = {
28                    Class = ConfigurationDatabase
29                    param1 = 2
30                }
31            }
32        }
33        +ENTER = {
34            Class = ReferenceContainer
35            +InformStatusUpdate = {
36                Class = Message
37                Destination = "EPICSCA.PV_STATUS"
38                Function = CAPut
39                Mode = ExpectsReply
40                +Parameters = {
41                    Class = ConfigurationDatabase
42                    param1 = 0
43                }
44            }
45        }

Running the application

  1. Start the softIOC in a separate terminal:

../Test/Integrated/GenerateEPICSSoftIOCDb.sh
softIoc -d ../Test/Integrated/MassSpring-1.db

  1. Start the MARTe2 application:

make -C ../Configurations/MassSpring/ -f Makefile.cfg
./MARTeApp.sh -f ../Configurations/MassSpring/RTApp-MassSpring-56_Gen.cfg -l RealTimeLoader -m StateMachine::START

  1. Verify that the application runs correctly. The log should show entries similar to:

$ |E=Information|TM=13:35:40 (7271154714286675)|o=StateMachine|O=0x000000000247CED0|C=StateMachine|T=|P=x86-linux|f=virtual MARTe::ErrorManagement::ErrorType MARTe::StateMachine::SendMultipleMessagesAndWaitReply(MARTe::ReferenceContainer, const MARTe::TimeoutType&)|F=StateMachine.cpp:340|D=In state (INITIAL) triggered message (StartNextStateExecutionRTApp)
$ |E=Information|TM=13:35:40 (7271154714327563)|o=StateMachine|O=0x000000000247CED0|C=StateMachine|T=|P=x86-linux|f=virtual MARTe::ErrorMManagement::ErrorType MARTe::StateMachine::SendMultipleMessagesAndWaitReply(MARTe::ReferenceContainer, const MARTe::TimeoutType&)|F=StateMachine.cpp:340|D=In state (WAVEFORM_REF) triggered message (InformStatusUpdate)
$ |E=Information|TM=13:35:41 (7271155716506427)|o=|O=0x0000000002540BE0|C=LoggerBroker|T=|P=x86-linux|f=virtual bool MARTe::LoggerBroker::Execute()|F=LoggerBroker.cpp:152|D=Time [0:0]:1000000
$ |E=Information|TM=13:35:41 (7271155716512697)|o=|O=0x0000000002540BE0|C=LoggerBroker|T=|P=x86-linux|f=virtual bool MARTe::LoggerBroker::Execute()|F=LoggerBroker.cpp:152|D=ReferencePosition [0:0]:0.400000
...

Open another terminal and change the application state by writing to the command PV:

caput MARTE2-TUTORIAL-USERNAME-APP-COMMAND 0
caput MARTE2-TUTORIAL-USERNAME-APP-COMMAND 1

Replace USERNAME with your username in capital letters.

Monitor the application state:

camonitor MARTE2-TUTORIAL-USERNAME-APP-STATUS

The PV should update (e.g. value 1), indicating a state change.

At the same time, the application log will reflect the new behaviour. For example, when switching to a constant reference state:

|E=Information|TM=13:40:35 (7271449679705588)|o=|O=0x0000000001C6DBE0|C=LoggerBroker|T=|P=x86-linux|f=virtual bool MARTe::LoggerBroker::Execute()|F=LoggerBroker.cpp:152|D=ReferencePosition [0:0]:2.000000