In the engineering practice of industrial variable frequency drive systems, the accuracy and flexibility of motor temperature monitoring directly affect the safety and control performance of the equipment. Traditional PTC thermistors only provide over temperature protection for switch values, and cannot achieve continuous temperature measurement and real-time display - this limitation is particularly prominent in applications that require precise temperature compensation or status monitoring. The Bonfiglioli Vectron ACTION and ACTION Cube series frequency converters, through the EM-IO-04 expansion module, integrate the CAN system bus and introduce the continuous temperature measurement capability of KTY temperature sensors. They also provide configurable digital ports (input/output switchable) and PNP/NPN selectable digital input logic, providing a highly integrated hardware solution for complex motor control and protection requirements.
Overview and Functional Positioning of EM-IO-04 Expansion Module
1.1 Module Core Functions
EM-IO-04 is an optional hardware expansion component designed by Bonfiglioli Vectron for the ACTION and ACTION Cube series frequency converters, supporting software versions 4.2.1 and higher for the ACTION series and all ACU series devices. This module achieves the following functional extensions by inserting it into the lower expansion slot of the frequency converter:
CAN system bus interface: Complies with ISO-DIS 11898 (CAN High Speed) standard, supports up to 1 MBaud communication rate, and is optically isolated
Digital port (EM-S1IOD): can be switched to digital input or digital output through parameters
Two digital inputs (EM-S2IND, EM-S3IND): supports PNP (high level effective) or NPN (low level effective) optional
Motor temperature assessment:
PTC thermistor or bimetallic temperature sensor (normally closed contact) - limit monitoring
KTY Temperature Sensor (KTY84/130) - Continuous Temperature Measurement and Display
Three 20V auxiliary power outputs
1.2 Comparison of EM-IO series functions
Function EM-IO-01 EM-IO-02 EM-IO-03 EM-IO-04
CAN system bus support support support support (optoelectronic isolation)
Analog input 1 channel 1 channel 1 channel 1 channel none
Analog output 1 channel (voltage) 1 channel (voltage) 2 channels (voltage+current) None
Digital input 3 channels 3 channels 2 channels 2 channels+1 channel configurable
Relay output 2, 1, 1 None
PTC limit monitoring not supported, supported, supported
KTY continuous temperature measurement is not supported
PNP/NPN optional, unsupported, unsupported, unsupported
Key differentiation value: EM-IO-04 is the only module in the EM-IO series that supports continuous temperature measurement with KTY temperature sensors, while providing unique configurable digital ports and PNP/NPN logic selection functions. It sacrifices analog channels in exchange for the most comprehensive motor temperature monitoring solution and maximum digital I/O flexibility.
Key points of mechanical and electrical installation
2.1 Mechanical Installation
The installation steps are consistent with other modules in the EM-IO series:
Power off confirmation: The frequency converter is completely powered off and waiting for the DC bus capacitor to discharge completely.
Disassemble the lower cover plate: Remove the plastic cover plate on the lower part of the frequency converter.
Insertion module: Align the EM-IO-04 expansion module with the slot and apply even force to insert it, holding only the housing and avoiding contact with the PCB.
Reset cover plate: Reinstall the lower cover plate.
2.2 Electrical Connections - Detailed Explanation of Terminal Definitions
The terminal layout of EM-IO-04 differs significantly from EM-IO-01/02/03 and requires special attention.
Socket X410A (terminals 1-7):
Technical parameter description of terminal signal
1 20V output Imax=180mA auxiliary power supply
2 20V ground - corresponding to terminal 1 ground
3 digital inputs 2 (EM-S2IND) PNP/NPN optional speed sensor Track A
4 20V output Imax=180mA auxiliary power supply
5 20V ground - corresponding to terminal 4 ground
6-digit input 3 (EM-S3IND) PNP/NPN optional speed sensor Track B
7 20V output Imax=180mA auxiliary power supply
Socket X410B (terminals 1-7) - The temperature sensor interface is located in this socket:
Technical parameter description of terminal signal
1-2 temperature sensors (EM-MPTC/EM-KTY) PTC:>2.4k Ω response/KTY: 424~1722 Ω S3 switch selection mode
3 Digital Ports (EM-S1IOD) Input: 30V/16mA/Output: 24V/40mA Parameter 558 Switching
4 20V Ground - Digital Port Ground
5 CAN_Low - System Bus CAN Low Line
6 CAN-High - System Bus CAN High Line
7 CAN_SND - System Bus Ground
Key Engineering Tips:
Terminal X410B. 1-2 is a dedicated interface for temperature sensors, and PTC or KTY mode can be selected through dip switch S3.
Terminal X410B. 3 is a digital port that switches input/output modes through parameter 558.
X410A provides three 20V auxiliary power supplies (terminals 1, 4, 7) with a total load capacity of 180mA, requiring power budgeting.
2.3 Temperature sensor type selection (dip switch S3)
S3 Position Mode Sensor Type Measurement Capability
Right side (OFF) EM-MPTC PTC thermistor (DIN 44081) or bimetallic temperature sensor (normally closed contact) limit monitoring (switch quantity)
Left (ON) EM-KTY KTY84/130 temperature sensor continuous temperature measurement (analog quantity)
Motor temperature monitoring - detailed explanation of core differentiation functions
The most significant feature of EM-IO-04 is its dual temperature monitoring capability: it supports both PTC switch limit protection and KTY continuous temperature measurement.
3.1 PTC/bimetallic temperature sensor limit monitoring (S3=right side)
When S3 is placed on the right side (EM-MPTC mode), the module evaluates the resistance change of PTC thermistor or bimetallic temperature sensor (normally closed contact). The rated response resistance value of PTC is>2.4k Ω (in accordance with DIN 44081).
Operation mode (parameter 570) - consistent with EM-IO-02/03:
Application of Mode Function Engineering
Only display a warning when overheating occurs, without triggering a shutdown
12. Immediately report fault F0400 and stop the machine freely
13 fault shutdown, delayed for 1 minute, short-term overheating tolerance
14 fault shutdown, delayed for 5 minutes, suitable for overheating during the start-up phase
15 fault shutdown, with a maximum tolerance delay of 10 minutes
3.2 KTY Temperature Sensor Continuous Temperature Measurement (S3=Left) - Core New Function
This is the core function that distinguishes EM-IO-04 from EM-IO-01/02/03. When S3 is placed on the left side (EM-KTY mode), the module evaluates the KTY84/130 temperature sensor and achieves continuous temperature measurement from -20 ° C to 200 ° C.
Technical specifications of KTY84/130 sensor:
Resistance value at 100 ° C: 1000 Ω
Temperature coefficient of resistance: 0.61%/K (at 100 ° C ambient temperature)
Resistance range: 424 Ω~1722 Ω (corresponding to measurement range of -20 ° C~200 ° C)
Temperature measurement parameterization:
Select mode 22- Temp. Meas. with EM-KTY through parameter 465 (Operation Mode) to enable KTY temperature measurement.
The actual temperature value can be read through parameter 226 (Winding Temperature).
The maximum allowable winding temperature is set through parameter 617 (max. Temp. Windings), with a range of 50 ° C~200 ° C and a factory value of 150 ° C.
KTY temperature over limit response mode (parameter 570):
Mode Function Engineering Description
Only display a warning when the maximum. Temp. Windings are exceeded
22 fault shutdown immediately reports fault F0400
23 fault shutdown, delayed for 1 minute, short-term over temperature tolerance
24 fault shutdown, delayed for 5 minutes, suitable for motors with high thermal inertia
25 fault shutdown, with a maximum tolerance delay of 10 minutes
The engineering value of KTY temperature measurement:
Continuous temperature display: Operators can monitor the temperature of the motor winding in real time and predict the risk of overheating
Optimization of control parameters: Temperature values can be used to synchronize temperature related control parameters (such as stator resistance compensation in magnetic field orientation control)
Trend analysis: Judging the motor load status or cooling system efficiency through temperature change trends
Accurate protection: Compared to PTC's switch protection, KTY can achieve more precise over temperature protection threshold setting

Digital port configuration
4.1 Port mode switching
The digital port of terminal X410B. 3 can switch function through parameter 558 (Operation Mode):
Mode Function Description
0-input digital input can be used as a control signal source (such as start/stop)
1-output digital output can be used as a status indicator or to control external devices
When used as a numerical input (mode 0):
The operation mode is selected through parameter 559 (Operation Mode Output)
Can be linked to any parameterized input function inside the frequency converter
Signal source numbers: 320 (EM-S1IND), 520 (EM-S1IND inverted)
As a digital output (Mode 1):
The operation mode selection is the same as the digital output of the inverter body
Output characteristics: High level=24V, Imax=40mA, PLC compatible
PNP/NPN Logic Selection - Expanding Application Flexibility
The digital inputs EM-S2IND (X410A. 3) and EM-S3IND (X410A. 6) of EM-IO-04 support selecting PNP (high level effective) or NPN (low level effective) logic through parameters, which is the only module in the EM-IO series that has this function.
Logical selection (through numerical input operation mode):
The mode function is applicable to sensor types
0-HIGH-switching PNP input, high level (≥ 13V) effective standard PNP type proximity switch, photoelectric sensor
1-LOW switching NPN input, low level (≤ 5V) effective NPN sensor, PLC output
Signal source number:
EM-S2IND: 321 (positive logic)/521 (negative logic)
EM-S3IND: 322 (positive logic)/522 (negative logic)
Engineering value: This feature enables EM-IO-04 to be directly compatible with the vast majority of industrial sensor types on the market, without the need for external level conversion circuits, significantly simplifying on-site wiring.
Fixed frequency extension
EM-IO-04 expands the fixed frequency to 8 groups through parameter 131 (Fixed frequency change over 3):
Fixed frequency parameter FF3=0 FF3=1
Fixed frequency 5 485 0 1
Fixed frequency 6 486 1 1
Fixed frequency 7 487 1 0
Fixed frequency 8 488 0 1
CAN system bus configuration
The system bus interface of EM-IO-04 has optoelectronic isolation characteristics, enhancing its anti-interference ability in industrial electromagnetic environments.
7.1 Terminal resistor configuration (dip switch S1/S2)
Passive terminal (S1=ON, S2=OFF): Conventional terminal matching
Active terminal (S1=ON, S2=ON): Improve the shape of CAN signal edges
Factory default: S1 and S2 are both OFF
7.2 Node ID and Baud Rate
Parameter Description Range Factory Value
900 Node-ID-1~63-1 (disabled)
903 Baud-Rate 3~8 —
Set rules:
Node ID=-1: System bus disabled
Node ID=0: defined as the main station (only one is allowed)
Node ID=1~63: Slave address
7.3 Virtual Links
EM-IO-04 supports horizontal data transmission between frequency converters through TxPDO/RXPDO:
TxPDO channel Boolean parameter Word parameter Long parameter
TxPDO1 946~949 950~953 954~955
TxPDO2 956~959 960~963 964~965
TxPDO3 966~969 972~975 976~977
Digital signal state coding
The digital input/output status is read as decimal values through parameters 250 (Digital inputs) and 254 (Digital outputs) and needs to be converted to binary:
Position allocation:
Bit 3 (decimal 8): Digital port EM-S1IOD output status (when configured as output)
Bit 7 (decimal 128): Digital port EM-S1IOD input status (configured as input)
Bit 8 (256 decimal): Digital input EM-S2IND
Bit 9 (decimal 512): Digital input EM-S3IND
Quick Reference Table for Fault Codes
Fault code description and troubleshooting suggestions
F0400 motor temperature exceeding limit or temperature sensor connection fault inspection X410B. 1-2 wiring and sensor status
F1450 KTY temperature sensor measurement fault check whether S3 is on the left side (KTY mode) and whether the sensor resistance is within the effective range
F21nn system bus slave fault check corresponding node (nn hexadecimal)
F2200 SYNC message timeout check for main station SYNC generation
F2210 CAN bus BUS-OFF check for physical connections, terminal resistance, and baud rate
Bus load planning reference
Baud rate (kBaud) message transmission time (μ s)
1000 140
500 280
250 560
125 1120
100 1400
50 2800
Load assessment: A total load rate of ≤ 80% for all TxPDOs is normal, and>90% is unacceptable.
