Communication Bus Failure in Roll Forming Machines – Causes, Network Loss, Inspection & Repair Guide
Communication Bus Failure
Roll Forming Machine Electrical & PLC Failure Guide
Communication bus failure is a control network fault in roll forming machines where the industrial communication system connecting the PLC to other machine devices stops functioning correctly.
Modern roll forming machines use industrial communication networks, often called fieldbus or communication buses, to connect multiple automation components.
These networks allow devices to exchange data in real time so the machine can operate with precise coordination.
Common devices connected through communication buses include:
PLC controllers
remote I/O modules
servo drives
variable frequency drives (VFDs)
HMI operator interfaces
encoder interfaces
safety controllers
Typical industrial communication systems used in roll forming machines include:
Ethernet/IP
PROFINET
Modbus
CANbus
EtherCAT
Profibus
These communication networks allow the PLC to send commands and receive feedback from connected equipment.
For example, the PLC may communicate with servo drives to control flying shear movement or exchange data with remote I/O modules monitoring sensors.
If the communication network fails or becomes unstable, devices may stop exchanging data.
This condition is known as communication bus failure.
Communication bus failures commonly affect roll forming machines producing:
metal roofing panels
metal wall cladding panels
standing seam roofing systems
structural deck profiles
C and Z purlins
light gauge steel framing components
Typical production symptoms associated with communication bus failure include:
PLC communication alarms
devices appearing offline in the PLC system
servo drives not responding to commands
machine stopping unexpectedly
HMI losing connection to the PLC
loss of sensor signals from remote I/O modules
Because modern roll forming machines rely heavily on communication networks, a bus failure can stop the entire machine until communication is restored.
Causes of Wear or Failure
Communication bus failure typically occurs due to wiring problems, device faults, or network configuration issues.
Several factors may contribute to this condition.
Damaged Communication Cables
Broken or damaged cables may interrupt network signals.
Loose Network Connectors
Poor cable connections may disrupt communication.
Electrical Noise Interference
Electromagnetic interference may corrupt data signals.
Faulty Network Devices
Failed drives or modules may disrupt network communication.
Incorrect Network Configuration
Incorrect addresses or parameters may prevent communication.
Power Loss to Network Devices
Devices without power cannot participate in the network.
Why It Happened and What Caused It
From an automation engineering perspective, industrial communication networks operate by transmitting digital data packets between devices using defined protocols.
Each device connected to the network must maintain continuous communication with the PLC.
If a device stops responding or if the network signal becomes corrupted, the PLC may detect a communication fault.
Communication failures may occur when cables become damaged or disconnected.
Industrial networks are also sensitive to electrical interference generated by motors, drives, and switching equipment.
Improper cable shielding or routing may allow this interference to disrupt communication signals.
In some cases, a single faulty device on the network may cause communication interruptions for the entire bus.
Maintaining proper wiring practices and device configuration helps ensure stable network communication.
How to Inspect the Problem
Inspection Procedure
Diagnosing communication bus failure requires inspecting both the physical network wiring and the device configuration.
Step 1 – Check PLC Communication Alarms
Review PLC diagnostic messages related to network communication.
Step 2 – Inspect Network Cables
Look for damaged or disconnected cables.
Step 3 – Inspect Network Connectors
Ensure connectors are securely attached.
Step 4 – Check Device Status Indicators
Observe LEDs on network devices to determine communication status.
Step 5 – Verify Device Power Supply
Ensure all network devices are powered correctly.
Step-by-Step Technician Guide – How to Fix
Correcting communication bus failure usually requires restoring network connectivity and resolving device issues.
Method 1 – Replace Damaged Communication Cables
Install new network cables if wiring is damaged.
Method 2 – Secure Network Connectors
Ensure connectors are firmly attached.
Method 3 – Reset Network Devices
Restart drives or modules that have stopped responding.
Method 4 – Correct Network Configuration
Verify addresses and communication settings.
Method 5 – Replace Faulty Devices
Install new network components if necessary.
Preventative Maintenance Tips
Preventing communication bus failure requires maintaining network wiring and device configuration.
Inspect Communication Cables Regularly
Routine checks help detect cable damage.
Maintain Proper Cable Shielding
Shielded cables reduce electrical interference.
Secure Network Connections
Stable connections prevent signal interruptions.
Monitor Network Diagnostics
Early detection of communication errors improves reliability.
Protect Network Equipment
Proper installation helps prevent environmental damage.
FAQ Section
What is communication bus failure in roll forming machines?
It occurs when the industrial communication network between the PLC and other devices stops functioning.
What causes communication bus failure?
Cable damage, loose connectors, device faults, or network configuration errors may cause failure.
Can communication failure stop machine production?
Yes. If critical devices lose communication with the PLC, the machine may stop.
How can communication bus failure be detected?
PLC diagnostic messages and device status indicators often show communication errors.
Can electrical noise affect communication networks?
Yes. Electromagnetic interference may disrupt network signals.
How can communication bus failure be prevented?
Proper cable installation, shielding, and regular network inspection help maintain reliable communication.