In modern frequency converter drive systems, the scalability of functions and the flexibility of communication have become the core considerations for equipment selection and system integration. The Bonfiglioli Vectron ACTION and ACTION Cube series inverters provide users with rich I/O expansion capabilities and powerful CAN system bus communication functions through the EM-IO-01 expansion module, enabling seamless integration of inverters into distributed control architectures and achieving efficient data exchange and collaborative control.
This article is based on the EM-IO-01 expansion module technical manual and provides a systematic technical operation guide for the core concerns of on-site engineers in installation, configuration, and system integration processes. It covers hardware installation, electrical connections, system bus configuration, PDO/SDO communication mechanisms, and I/O parameterization applications.
Overview and Preparation Before Installation of EM-IO-01 Expansion Module
1.1 Module Function Positioning
EM-IO-01 is an optional hardware expansion component designed by Bonfiglioli Vectron for the ACTION and ACTION Cube series frequency converters, supporting software versions 4.1.0 and higher for the ACTION series and all ACU series devices. This module achieves the following functional extensions by inserting it into the expansion slot at the bottom of the frequency converter:
CAN system bus interface: compliant with ISO-DIS 11898 (CAN High Speed) standard, supporting a maximum communication rate of 1 MBaud
Second bipolar analog input: 12 bit resolution, configurable for ± 10V voltage or ± 20mA current input
Second bipolar analog output: ± 10V voltage output, overload and short circuit protection
Three channel digital input: PLC compatible, 24V level, supports up to 150kHz frequency signal
Two relay outputs: normally open contacts, 24V AC/DC, 1A (resistive load)
1.2 Safety confirmation before installation
Danger Warning: The installation and removal of the EM-IO-01 expansion module must be carried out with the frequency converter completely powered off. The main power supply, DC bus, and motor terminals of the frequency converter may still carry dangerous voltage even after a power outage, and must wait for the DC bus capacitor to discharge completely (several minutes) before operation can be carried out.
Anti static precautions: The module is pre installed in a dedicated housing when it leaves the factory. During installation, do not touch the PCB board on the back of the module to avoid electrostatic discharge damaging sensitive electronic components.
Mechanical installation steps
2.1 Disassemble the lower cover plate
Confirm that the frequency converter has been completely powered off and discharged.
Find the plastic cover plate under the frequency converter (position 1) and carefully remove it.
After removing the cover, the expansion slot (position 3) is exposed.
2.2 Inserting Expansion Modules
Take out the EM-IO-01 expansion module (position 2), be careful to hold only the housing part and avoid touching the back PCB.
Align the module with slot (position 3) and apply even force to fully insert it.
Reinstall the lower cover plate (position 1) to complete the mechanical installation.
Attention: The module insertion direction has a foolproof design. If insertion is difficult, do not apply force forcefully and check if the direction is correct.
Definition of Electrical Connections and Terminals
3.1 Overview of Terminal Layout
The EM-IO-01 module provides two sockets: X410A and X410B.
Socket X410A (terminals 1-7):
Engineering Description of Terminal Signal Technical Parameters
1 20V output Imax=180mA to power external sensors
2 20V ground - corresponding to terminal 1 ground
3-digit input 1 (EM-S1IND) Umax=30V, 10mA@24V , PLC compatible response time is about 16ms
4-digit input 2 (EM-S2IND) can be used as the speed sensor Track A as above
5 digital inputs 3 (EM-S3IND) can be used as the speed sensor Track B as above
6-7 Relay Output 1 (EM-S1OUTD) 24V AC/DC, 1A normally open contact
Socket X410B (terminals 1-7):
Engineering Description of Terminal Signal Technical Parameters
1-2 relay output 2 (EM-S2OUTD) 24V AC/DC, 1A normally open contact
3 Analog inputs (EM-S1INA) ± 10V (Ri=100k Ω)/± 20mA (Ri=250 Ω) 12 bit resolution
4 Analog Output (EM-S1OUTA) ± 10V, Imax=2mA Overload and Short Circuit Protection
5 CAN_Low - System Bus CAN Low Line
6 CAN-High - System Bus CAN High Line
7 CAN_SND - System Bus Ground
Key Tip: The maximum load current for the 20V output of terminal X410A. 1 is 180mA, and this current shares the total capacity with other control outputs of the inverter body. When designing external circuits, power budgeting is required.
3.2 Analog Input Voltage/Current Mode Switching
The module is equipped with a dip switch S3 for configuring the analog input signal type:
S3=OFF (right side): The analog input is configured as a voltage signal (± 10V)
S3=ON (left side): Analog input configured as current signal (± 20mA)
Note: S1 and S2 switches are used for configuring the terminal resistance of the system bus (see System Bus chapter for details).
CAN system bus configuration
4.1 Bus topology and terminal resistance
The system bus of EM-IO-01 adopts CAN High Speed physical layer, which complies with ISO-DIS 11898 standard. The bus topology is a linear structure (daisy chain), and terminal resistors must be set at the first and last physical nodes.
The module is configured with terminal resistors through dip switches S1 and S2
Passive terminal (S1=ON, S2=OFF): Conventional terminal matching
Active terminal (S1=ON, S2=ON): Active terminal, can improve the shape of CAN signal edges, suitable for long-distance buses
Factory default: S1 and S2 are both OFF (terminal resistance not activated).
Important note: Active terminals can only be activated on one node of the bus, and other nodes must use passive terminals. Improper configuration of terminal resistors will result in bus communication errors.
4.2 Node ID Setting
The system bus supports up to 63 slave nodes (frequency converters), and each node must have a unique Node ID. Node ID is set through parameter 900:
Parameter Description Minimum Value Maximum Value Factory Value
900 Node-ID -1 63 -1
Node ID=-1: The system bus disables this frequency converter
Node ID=0: Define this frequency converter as the bus master station (only one master station is allowed)
Node ID=1~63: Slave address
4.3 Baud rate and bus length
All bus nodes must be set to the same baud rate. The baud rate is set through parameter 903 and determines the maximum bus length:
Maximum line length for operating mode baud rate
3 50 kBaud 1000 meters
4 100 kBaud 800 meters
5 125 kBaud 500 meters
6 250 kBaud 250 meters
7500 kBaud 100 meters
8 1000 kBaud 25 meters
Engineering Tip: Baud rates below 50 kBaud are not recommended for low data throughput on the system bus. The actual maximum line length needs to be calculated and verified based on cable parameters and bus driver (PCA82C250T).

System bus communication mechanism
The system bus of the EM-IO-01 module is based on the CANopen protocol framework (CiA DS 301), which enables communication between Network Management (NMT), Process Data Objects (PDO), and Service Data Objects (SDO).
5.1 Network Management (NMT) and Startup Sequence
The node state machine on the system bus contains three main states:
Pre Operational: Only SDO communication (parameter read/write) is allowed, PDO (process data) is prohibited
Operational: Both SDO and PDO are allowed
Stopped: Both SDO and PDO are prohibited
Typical startup sequence:
After power on, all slave stations complete initialization and enter Pre Operational state
Send Boot Up message from the slave station (identifier=1792+Node-ID, data byte=0x00)
The master station switches the slave station to Operational state through the NMT command "Start Remote Node" (command code=1)
After initialization is completed, the master station periodically sends the Start Remote Node command with the delay time set by parameter 904 (Boot Up Delay) to ensure that the slave stations that are delayed online or temporarily disconnected can resume normal communication
Main station fault response: When the main station receives an Emergency Message from the slave station, its response is set by parameter 989 (Emergency Reaction):
989=0 (Error): The master station shuts down simultaneously and reports the fault to the slave station through fault code F21nn (nn is the hexadecimal of the slave station Node ID)
989=1 (No Error): The main station only reports a warning (Sysbus 0x2000)
5.2 SDO Channel (Parameter Data)
Each frequency converter has two SDO channels for parameter data exchange:
SDO1: Used for parameterized access of slave stations by the master station (PLC/PC or frequency converter master station)
SDO2: Reserved for parameterization by visualization tools (such as VPlus software)
The SDO channel adopts the CANopen SDO Segment Protocol Expedited service, which supports read and write of uint/int/long type data. Complete parameterization can be achieved through the system bus.
SDO1 identifier allocation (Predefined Connection Set):
Rx-SDO1=1536+Node ID (identifier range 1537~1599)
Tx-SDO1=1408+Node ID (identifier range 1409~1471)
Fixed allocation of SDO2 identifiers:
Rx-SDO2 = 1600 + Node-ID
Tx-SDO2 = 1472 + Node-ID
Note: In CANopen systems, SDO2 must be disabled to avoid compatibility issues. The activation state of SDO2 can be controlled through parameter 923 (SDO2 Set Active).
5.3 PDO channel (process data)
Each frequency converter has three PDO channels (three Rx/Tx each) for high-speed process data exchange. The PDO channel can operate in two modes: time control or SYNC control.
PDO identifier allocation (Predefined Connection Set):
Channel Rx identifier Tx identifier
PDO1 512 + Node-ID 384 + Node-ID
PDO2 768 + Node-ID 640 + Node-ID
PDO3 1024 + Node-ID 896 + Node-ID
Operation mode setting:
TxPDO Function (parameters 930/932/934): 0=disabled, 1=time control, 2=SYNC control
RxPDO Function (parameters 936/937/938): 0=time control (immediate forwarding), 1=SYNC control
Attention: The identifier range of 129~191 is reserved for emergency messages and cannot be used for PDO allocation.
5.4 Virtual Links
The most distinctive feature of the system bus is the virtual link mechanism. By linking the source data to the sending byte of TxPDO and linking the receiving byte of RxPDO to the target parameter, horizontal data transmission between frequency converters can be achieved.
TxPDO byte mapping parameters:
Channel data type parameter number (bytes 1-4/5-8)
TxPDO1 Boolean 946, 947, 948, 949
TxPDO1 Word 950, 951, 952, 953
TxPDO1 Long 954, 955
TxPDO2 Boolean 956, 957, 958, 959
TxPDO2 Word 960, 961, 962, 963
TxPDO2 Long 964, 965
TxPDO3 Boolean 966, 967, 968, 969
TxPDO3 Word 972, 973, 974, 975
TxPDO3 Long 976, 977
Example of Source Number:
Boolean source: 740=control word, 161=running status
Word source: 9063=percentage reference value 11133=output percentage
Long source: 900=output frequency, 62=reference frequency value
RxPDO receiving source number: The data received by RxPDO is presented through source numbers 700~729 (RxPDO1), 710~719 (RxPDO2), and 720~729 (RxPDO3), which can be used locally through parameter links.
Detailed configuration of analog input/output
6.1 Analog input characteristic curve
The analog input signal is mapped to a frequency or percentage reference value through a two-point linear characteristic curve. Two characteristic points are set through parameters 564-567:
Parameter Description Range Factory Value
564 characteristic point X1-1000.00%~100.00% -98.00%
565 characteristic point Y1-1000.00%~100.00% -1000.00%
566 characteristic point X2-1000.00%~100.00% 98.00%
567 characteristic point Y2-1000.00%~100.00% 100.00%
Calculation formula for characteristic curve:
Y=Y two−Y one X two−X one⋅(X−Xone)+Y one
Y= X2−X1 Y2−Y1⋅(X−X1)+Y1
Operation mode (parameter 562):
1. Bipolar: Complete mapping according to characteristic points
11- Unipolar: Mapping negative X-axis value to reference value 0
21- Monopolar 2... 10V/4... 20mA: Limit the input range to 20%~100%
101- Bipolar absolute value: negative Y-axis value mapped to positive reference value
6.2 Tolerance bands and hysteresis
For applications that require switching the direction of rotation, the tolerance band (parameter 560) is used to expand the range of the reference value crossing zero, avoiding frequent direction switching near zero and causing system oscillation. The parameter range is 0.00%~25.00%, and the factory value is 2.00%.
6.3 Fault/Warning Behavior (Parameter 563)
Mode function
0-OFF does not monitor input signals
When the warning signal is less than 1V/2mA, a warning will be issued
When the shutdown signal is less than 1V/2mA, slow down and stop the machine according to the shutdown mode
When the fault shutdown signal is less than 1V/2mA, the machine can stop freely and report a fault
6.4 Analog Output Configuration
Simulate output by selecting the output signal source through parameter 584 (operating mode), and adjusting the application level through parameters 585 (offset) and 586 (amplification factor). Set the zero offset as a percentage of the simulated output full range (10V); The amplification factor is set to the signal gain as a percentage of the full scale, ranging from 5% to 1000%.
Digital input as speed sensor (EM-ENC)
The three digital inputs of EM-IO-01 can be configured as an incremental speed sensor interface through parameter 493 (Operation mode speed sensor 2):
Mode Function Description
Four fold frequency evaluation of dual channel speed sensor, identifying direction through A/B phase signals, evaluating 4 edges per turn
On the basis of the fourth harmonic inversion, the velocity value is inverted (equivalent to exchanging A/B signals)
1004- Four fold increase in reference pulse with reference pulse for sensor monitoring
1104- with reference pulse reverse fourth harmonic as above, the velocity value is taken in reverse
Index mark (parameter 494): Set according to the number of pulses per revolution of the speed sensor, ranging from 1 to 8192, with a factory value of 1024.
Maximum division mark calculation:
Smax=one hundred and fifty thousand Hz×sixty n max
S max=150000Hz× n max sixty
Among which
n max For the maximum speed (RPM) of the motor, 150kHz is the maximum frequency limit for digital input.
Actual speed source selection (parameter 766): 1=speed sensor 1 (body), 2=speed sensor 2 (EM-IO-01).
Bus load planning
The capacity planning of the system bus is crucial for reliable communication. Each PDO message contains 8 bytes of user data, and in the worst case scenario, the total message length is 140 bits.
Single PDO message transmission time at different baud rates:
Baud rate (kBaud) message transmission time (μ s)
1000 140
500 280
250 560
125 1120
100 1400
50 2800
Bus load calculation formula:
Load=TelegramRunTime
TransmissionInterval×one hundred%
Load= TransmissionInterval
TelegramRunTime×100%
Load assessment criteria:
≤ 80%: Normal
80%~90%: critical
90%: unacceptable
Note: The sum of the total loads of all TxPDOs determines the overall load rate of the system bus. A margin must be reserved for message retransmission during design.
Common fault codes and troubleshooting
Fault code description and troubleshooting suggestions
F1402 Analog Input EM-S1INA Signal Fault Check Signal Source and Wiring, Confirm Signal is within Effective Range
F30 speed sensor 2 signal fault check sensor wiring and power supply
F31 speed sensor 2 phase loss signal check whether the A or B phase signal is lost
F32 Speed Sensor 2 Direction Error Check A/B Reverse Connection or Parameter Setting
F33 speed sensor 2 division mark error check parameter 494 whether the setting matches the sensor
F21nn system bus slave fault (nn is Node ID hexadecimal) check the corresponding node status and communication link
F2200 SYNC message timeout check whether the SYNC generation of the main station is normal
F2201~03 RxPDO1-3 timeout check corresponding to the TxPDO configuration and communication of the sending node
F2210 CAN bus BUS-OFF check for bus physical connection, terminal resistance, and baud rate consistency
