Bonfiglioli Vectron EM-ENC-03 Second Encoder Interface and System Bus Expansion Guide

max=300000Hz× n max 60s/min 

among which nmax

The maximum speed (RPM) of the motor.

Minimum number of lines required:

To ensure smooth operation at low speeds, the encoder signal should be updated at least every 2ms (signal frequency ≥ 500Hz). The formula for calculating the minimum number of lines is:

Smin=five hundred Hz×sixty s/min four×nmin

S min=500Hz× 4×n min 60s/min

The coefficient 4 represents the fourth harmonic evaluation,nmin

The minimum operating speed (RPM) of the motor.

2.3 Actual speed source switching

After the second encoder of EM-ENC-03 is connected, the feedback source of the speed controller can be selected through the parameter Actual Speed Source 766 (Chapter 5.1.4):

1 (Speed Sensor 1): Use the encoder input of the basic device (default)

2 (Speed Sensor 2): Use the second encoder input of EM-ENC-03

This feature allows users to flexibly switch between two encoders or switch to a backup encoder in case of a main encoder failure, achieving redundant feedback.

2.4 Encoder signal fault diagnosis

EM-ENC-03 extends encoder fault detection capability (Chapter 7.1):

F1430: Encoder signal fault (no signal), check the A+/A -, B+/B - wiring and encoder power supply of X410A.

F1431: Encoder single channel signal missing (phase A or B lost), check if the cable is open or has poor contact.

F1432: Encoder rotation direction error (A/B phase signal reversed), can be corrected by swapping A+and B+wiring.

Chapter 3: CAN System Bus and CANopen Protocol Stack

EM-ENC-03 integrates the complete CAN system bus function (Chapter 4), based on the CANopen protocol (CiA DS301), to achieve real-time data exchange and distributed control between frequency converters.

3.1 Node Address and Baud Rate Configuration

Node-ID 900 (Chapter 4.5): Set the node address (range -1~63). -1 is disabled (factory default), 0 is master mode. Only one main station is allowed in the network.

Baud Rate 903 (Chapter 4.4): Supports baud rate settings from 50 kbps to 1000 kbps. The lower the baud rate, the longer the allowed bus length (such as 50 kbps → 1000 meters, 1000 kbps → 25 meters).

3.2 Bus Terminal Resistance Configuration (DIP Switches S1 and S2)

The CAN bus requires terminal resistors to be configured at the first and last nodes of the physical bus (Chapter 4.1):

Passive terminal: S1=ON, S2=OFF (standard 120 Ω terminal)

Active terminal: S1=ON, S2=ON (improves signal edge through bias circuit, suitable for long-distance bus)

Key rules:

Active terminals are only allowed to be activated at one location within the network

Other terminal nodes must use passive terminals

Factory default S1 and S2 are both OFF

3.3 NMT State Machine and Network Startup Sequence

The system bus of EM-ENC-03 follows the CANopen NMT (Network Management) state machine (Sections 4.7, 4.8.1):

Three NMT states:

Pre Operational: The default state after power on initialization. Only SDO (Parameter Channel) is available, PDO (Process Data) is disabled.

Operational: Activate PDO communication to achieve real-time data exchange. Meanwhile, SDO can still be accessed.

Stopped: All communication is prohibited.

Main station startup process:

After the main station is powered on, wait for a configurable delay time (Boot Up Delay 904, default 3500ms), and then send the NMT command Start Remote Node (command word 0x01, node ID 0x00 represents broadcast) to switch all slave stations to Operational state.

3.4 Emergency message and main station fault response

When a fault occurs at the slave station, an Emergency Message is sent with an identifier of 128+Node ID (Chapter 4.8.3). The behavior of the main station is defined by the parameter Emergency Reaction 989:

989=0 (Error): After receiving an emergency message, the master station also tripped and reported fault F21nn (nn is the hexadecimal node ID of the faulty slave station), while the warning bit Sysbus (0x2000) was set.

989=1 (No Error): The main station only displays a warning and does not trigger its own trip.

Chapter 4: PDO Channel and Virtual Link Data Mapping

EM-ENC-03 supports three sets of PDO (Process Data Object) channels for real-time process data exchange between frequency converters (Chapter 4.11).

4.1 PDO identifier allocation

The default identifier follows the CANopen predefined connection set:

TxPDO1：384 + Node-ID

RxPDO1：512 + Node-ID

TxPDO2：640 + Node-ID

RxPDO2：768 + Node-ID

TxPDO3：896 + Node-ID

RxPDO3：1024 + Node-ID

Identifier uniqueness rule:

All TxPDO identifiers must be unique in the bus network

The identifier range of 129~191 is reserved for emergency messages and cannot be used for PDO

4.2 PDO working mode

Each PDO channel can be configured as (Chapter 4.11.2):

Time control: TxPDO sends cyclically at fixed time intervals (such as TxPDO1 Time 931); RxPDO forwards the data immediately after receiving it.

SYNC control: TxPDO sends the SYNC synchronization message uniformly after receiving it; RxPDO forwards data only after receiving SYNC. This mode is suitable for multi axis synchronous locking scenarios.

4.3 PDO timeout monitoring

Can enable RxPDO timeout monitoring (Chapter 4.11.3):

SYNC Timeout 939: Monitoring SYNC message timeout