20161016_DAEDALUS_Panel1_Speech2_NXTControl.ppsx

Example of how synchronization between PLCs can be problematic with IEC-61131

1. Daedalus as a digital platform for the
Factories of the Future
Distributed control and simulation platform to support an ecosystem of digital
automation developers
EC HORIZON2020
Project Co-Funded by the European Commission
Grant agreement: 723248
Call identifier: H2020 – FoF-11-2016
DAEDALUS

2. TASK 1
2
3
Distribution between scan based PLCs
EXEC
INPUT
OUTPUT
COM-
STACK
Data
Sync
EXEC
INPUT
OUTPUT
COM-
STACK
Data
Sync
IEEE 802.1 TSN
Worst case Delay
10ms Scan time
20ms Scan time
Thread >= 1 Threads

3. Distribution between scan based PLCs
Example A (IEC61131)
IEEE 802.1 TSN
FBR_TRIG.Q
CTU.CU
10ms (A)
20ms (B)
TRUE
TRUE
??
PLC-A PLC-B
10ms Scan time 20ms Scan time
Aliasing & Syncronity Problem

4. Distribution between scan based PLCs
EXEC
INPUT
OUTPUT
COM-
STACK
Data
Sync
EXEC
INPUT
OUTPUT
COM-
STACK
Data
Sync
IEEE 802.1 TSN
Worst case Delay
10ms Scan time 20ms Scan time
Disadvantages “MANUFACTURER”
–Heavy integration of Scan based Runtime with Real-time Communication stacks
–Message & Event Features of Real Time Stacks are heavy to support
–Synchronization difficult to implement
–Multicore CPUs can‘t be used for Scan based Execution (need Distribution too)
Disadvantages “USER”
–Aliasing & Syncronity can’t be solved by TSN, DDS or any other Real Time COM
–Oversampling only in one direction
–Hop delay = Scan time per Node
–Automatic code generation for communication applications impossible
–Non transparent execution <-> communication model even Multitasking is used

5. Distribution with IEC61449 (Event) based PLCs
COM-
STACK
COM-
STACK
IEEE 802.1 TSN
Worst case Delay
FB-Network
Extern
Event
Queue
Internal
Event
Queue
Scheduler
IN
OUT
FB-Network
Extern
Event
Queue
Internal
Event
Queue
Scheduler
IN
OUT
PLC-A PLC-B

6. Distribution with IEC61449 (Event) based PLCs
Example B (IEC61499) distribute anyway
PLC-A PLC-B

7. Distribution with IEC61449 (Event) based PLCs
Example B (IEC61499) real-time
PLC-A PLC-B
h
h
h h h h h
TSN TSN TSN TSN TSN TSN
Tpe
Publisher
Event Receiver
Data Receiver
COM-
STACK
COM-
STACK
h =Tpe + Tws1 + Tws2 + max(Ter,Tdr)
Tpe
Tws1 Tws2
Ter
Tdr
+h
exec
T = < T#100us

8. Distribution with IEC61449 (Event) based PLCs
COM-
STACK
COM-
STACK
IEEE 802.1 TSN
Worst case Delay
FB-Network
Extern
Event
Queue
Internal
Event
Queue
Scheduler
IN
OUT
FB-Network
Extern
Event
Queue
Internal
Event
Queue
Scheduler
IN
OUT
PLC-A PLC-B Advantages “USER”
–Clear context between Data & Execution (Event)
–Easy drag and drop mapping for distributed applications
–Smallest hop delay (few µs)
–Automatic code generation for communication applications possible
–Analysis of Real-Timing behavior and observation direct in application
–Debugging & functional Simulation

Advantages “MANUFACTURER”
–easy integration of FB-Runtime with Real-Time stacks
–Synchronization is done by the FB-Runtime
–Execution Models are clear definable
–Multicore support is easy possible (PS is done in shared Memory)