In the engineering practice of industrial variable frequency drive systems, the number and type of analog output channels often determine the signal interaction capability between the control system and the controlled equipment. For application scenarios that need to drive both voltage type actuators and current type instruments at the same time, a single analog output channel often becomes the bottleneck of system integration. The Bonfiglioli Vectron ACTION and ACTION Cube series frequency converters integrate a dual-mode analog output channel of one voltage output and one current output on the basis of standard functions through the EM-IO-03 expansion module, while retaining PTC temperature monitoring and CAN system bus communication capabilities, providing a highly integrated hardware solution for complex control requirements.
This article is based on the EM-IO-03 extension module technical manual, providing a systematic technical operation guide for the core concerns of on-site engineers in installation, wiring, dual analog output configuration, and PTC temperature monitoring process.
Overview and Functional Positioning of EM-IO-03 Expansion Module
1.1 Module Core Functions
EM-IO-03 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 lower expansion slot 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
Bipolar analog input: 12 bit resolution, configurable for ± 10V voltage or ± 20mA current input
Dual mode analog output:
Output 1: ± 10V voltage output (overload and short circuit protection)
Output 2:0 (4)~20mA current output (overload and short circuit protection)
Two way digital input: PLC compatible, 24V level, supports up to 150kHz frequency signal, can be used as speed sensor input
One way relay output: normally open contact, 24V AC/DC, 1A (resistive load)
PTC thermistor input: compliant with DIN 44081 standard, rated response resistance value of 2.85k Ω
1.2 Function Comparison of EM-IO-01/02/03 Series
Function EM-IO-01 EM-IO-02 EM-IO-03
CAN system bus support
Analog input 1 channel 1 channel 1 channel 1 channel
Analog output 1 channel (voltage) 1 channel (voltage) 2 channels (voltage+current)
Digital input: 3 channels, 3 channels, 2 channels
Relay output 2 channels, 1 channel, 1 channel
PTC temperature input not supported, supported
Key difference: EM-IO-03 sacrifices one digital input in exchange for an independent current analog output, making it an ideal choice for devices that require simultaneous control of voltage (such as variable frequency drive speed settings) and current (such as valve positioners and recorders).
Key points of mechanical and electrical installation
2.1 Mechanical Installation
The installation steps are exactly the same as EM-IO-01/02:
Power off confirmation: The frequency converter is completely powered off and wait for the DC bus capacitor to discharge completely (several minutes).
Disassemble the lower cover plate: Remove the plastic cover plate on the lower part of the frequency converter.
Insertion module: Align the EM-IO-03 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
EM-IO-03 provides two sockets: X410A and X410B.
Socket X410A (terminals 1-7) - Analog current output is located in this socket:
Technical parameter description of terminal signal
1 20V output Imax=180mA to power external sensors
2 20V ground - corresponding to terminal 1 ground
3 analog current output (EM-S2OUTA) 0 (4)~20mA, Umax=10V overload and short circuit protection
4-digit input 2 (EM-S2IND) Umax=30V, 10mA@24V Can be used as a speed sensor Track A
5 digital inputs 3 (EM-S3IND) can be used as the speed sensor Track B as above
6-7 relay output (EM-S1OUTD) 24V AC/DC, 1A normally open contact
Socket X410B (terminals 1-7) - The PTC interface and voltage output are located in this socket:
Technical parameter description of terminal signal
1-2 PTC Input (EM-MPTC) Rated Response Resistance 2.85k Ω (DIN 44081) Motor Temperature Monitoring
3 analog inputs (EM-S1INA) ± 10V/± 20mA, 12 bit second channel analog input
4 Analog Voltage 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:
Terminal X410A. 3 is for analog current output and can be directly connected to instruments or actuators that require 4-20mA or 0-20mA signals.
Terminal X410B. 4 is an analog voltage output that can simultaneously output ± 10V signals.
Terminals X410B. 1-2 are PTC thermistor inputs and support sensors that comply with DIN 44081 standards.