Communication options for Alicat instruments
Every Alicat device is equipped with at least one of the following communication protocols:
- Analog (4-20 mA, 0-10 Vdc, 0-5 Vdc, or 1-5 Vdc)
- ASCII over RS-232 or RS-485
- DeviceNET
- EtherCAT®
- EtherNet/IP
- IO-Link
- Modbus RTU over RS-232 or RS-485
- Modbus TCP/IP
- PROFIBUS
- PROFINET
ASCII and Modbus RTU over RS-232
Alicat devices come default with ASCII and Modbus RTU over RS-232. RS-232 interfaces are useful in systems with short-range, low-speed wired data connection. This is an inexpensive option when you only need to communicate with 26 to 32 devices in low-noise environments.
Modbus RTU has a simple setup and low memory requirement compared to most industrial protocols. It also has broad support among industrial control hardware and software systems. Modbus RTU has a standard set of universal commands, making it easy to use for those who are already familiar with the protocol.
ASCII or Modbus over RS-232 specifications
- Alicat part number: [default]; -MODBUS on older devices
- Analog signals: Yes
- Optional certifications: IP66/67; CSA Class 1/Div 2
- Electrical connections: Default 8 pin mini-DIN (other options available)
- Power over protocol connector: Available
- Dedicated power jack: Yes
- Additional power requirement: None
- Device compatibility: All devices**
- Available with display?: Yes
- Available via retrofitting to standard device?: Yes
- Software compatibility: Serial terminals (Alicat Terminal, HyperTerminal, PuTTy); FlowVision 2.0; LabVIEW; Modbus poll (Modbus only)
- Max number of devices on network: 26 (ASCII) or 32* (Modbus)
- Topologies: Linear; star
*BASIS devices can have 247 Modbus devices on a network.
**CODA not compatible with Alicat’s ASCII.
Resources
- Serial communications primer
- Modbus operating bulletin
- Modbus Poll Data Registers – MBP file – This loads the configuration requirements required to read the available data registers on any Modbus-equipped Alicat device and is useful for troubleshooting and viewing the required Modbus data settings.
Limitations
- Lower transmission speed compared with RS-485 and Ethernet.
- Operational across short distances only. Speed falls off considerably with distance.
- Not usable in high noise environments.
ASCII and Modbus RTU over RS-485
Choose ASCII and Modbus RTU over RS-485 if you are transmitting data across long distances or in a high noise environment. RS-485 can communicate with 26 to 32 devices at once, so larger systems will require an additional industrial protocol (see below).
ASCII over RS-485 is compatible with most devices, excluding CODA and portable options.
ASCII or Modbus RTU over RS-485 specifications
- Alicat part number: -485; -MODBUS-485 on older devices
- Analog signals: Yes
- Optional certifications: IP66/67; CSA Class 1/Div 2
- Electrical connections: Default 8 pin mini-DIN (other options available)
- Power over protocol connector: Available
- Dedicated power jack: Yes
- Additional power requirement: None
- Device compatibility: All devices except portables**
- Available with display?: Yes
- Available via retrofitting to standard device?: Yes
- Software compatibility: Serial terminals (Alicat Terminal, HyperTerminal, PuTTy); FlowVision 2.0; LabVIEW; Modbus poll (Modbus only)
- Max number of devices on network: 26 (ASCII) or 32* (Modbus)
- Topologies: Linear with termination resistor (120 Ohm)
Resources
- Serial communications primer
- Modbus operating bulletin
- Modbus Poll Data Registers – MBP file – This loads the configuration requirements required to read the available data registers on any Modbus-equipped Alicat device and is useful for troubleshooting and viewing the required Modbus data settings.
Limitations
- Connecting to a computer will typically require the purchase of an RS-485 card.
DeviceNET
DeviceNET is a common choice for automation or factory-type settings and can be used to communicate with up to 64 devices. This option has the most limited options for device configurations and is only available with standard devices with no display.
DeviceNET specifications
- Alicat part number: -DNET
- Secondary protocol: ASCII over RS-232 (primarily for debugging)
- Electrical connections: Male 5-pin M12 connector for DeviceNET (top port) and male 9-pin D-sub connector for RS-232 comms (side port)
- Power over protocol connector: Required
- Dedicated power jack: No
- Additional power requirement: 170 mA
- Device compatibility: Incompatible with CODA, BASIS, EPC, Class 1 Division 2, and portable devices
- Available with display?: No
- Available via retrofitting to standard device?: No
- Max number of devices on network: 64
- Topologies: Trunk with drop lines
Resources
Limitations
- Requires a PLC.
- Incompatible with CODA, BASIS, EPC, Class 1 Division 2, and portable devices.
- No display.
- No analog signals.
- More expensive than ASCII or Modbus.
- Requires 170 mA power.
EtherCAT
EtherCAT is the fastest industrial Ethernet technology, with data transmission rates up to 100 mbps.
EtherCAT specifications
- Alicat part number: -ECAT
- Electrical connections: Comms over dual RJ45
- Power over protocol connector: No
- Dedicated power jack: Required
- Additional power requirement: 120 mA
- Device compatibility: Incompatible with BASIS, EPC, Class 1 Division 2, and portable devices
- Available with display?: Yes
- Available via retrofitting to standard device?: No
- Network topologies: Star; linear
Resources
Limitations
- Requires a PLC.
- Incompatible with BASIS, EPC, Class 1 Division 2, and portable devices.
- No analog signals.
- More expensive than ASCII or Modbus.
- Requires 120 mA power.
EtherNet/IP
EtherNet/IP is one of the most popular industrial protocols, and can be thought of as a newer version of DeviceNET that is able to communicate with an unlimited number of devices. Like DeviceNET, it is only available with standard devices but has the added option of a display.
EtherNet/IP specifications
- Alicat part number: -EIP
- Electrical connections: Comms over dual RJ45
- Power over protocol connector: No
- Dedicated power jack: Required
- Additional power requirement: 120 mA
- Device compatibility: Incompatible with BASIS, EPC, Class 1 Division 2, and portable devices
- Available with display?: Yes
- Available via retrofitting to standard device?: No
- Max number of devices on network: No limit
- Topologies: Star; linear; ring
Resources
- EtherNet/IP operating bulletin
- EtherNet/IP EDS file
- EtherNet/IP Add-on Instructions (Alicat-EIP-Command)
- EtherNet/IP Add-on Instructions (Alicat-EIP-UpdateInput)
- ODVA Declaration of Conformity
Limitations
- Requires a PLC.
- Incompatible with BASIS, EPC, Class 1 Division 2, and portable devices.
- No analog signals.
- More expensive than ASCII or Modbus.
- Requires 120 mA power.
IO-Link
IO-Link is a bi-directional, digital, point-to-point industrial networking protocol. It allows users to directly interface with multiple devices via higher-level controller. Because of its compatibility with common industrial architectures, such as Fieldbus and industrial Ethernet, it can be easily connected to existing PLCs or HMIs using standard connectors.
IO-Link specifications
- Alicat part number: -IOLINKA (Class A) or -IOLINKB (Class B)
- Electrical connections: M12
- Power over protocol connector: Yes
- Dedicated power jack: No
- Device compatibility:Incompatible with Basis, CODA, Class 1 Div 1, Class 1 Div 2, and portable devices
- Available with display?: Yes
- Available via retrofitting to standard device?: No
- Max number of devices on network: Determined by the IO-Link master
Resources
- Manual
- IODD files and Manufacturer’s Declarations (links to IO-Link.com)
Limitations
- Requires an IO-Link master to be used
- Incompatible with Basis, CODA, Class 1 Div 1, Class 1 Div 2, and portable devices
Modbus TCP/IP
Modbus TCP/IP is the simplest of ethernet protocols and was created for integration with pre-existing TCP/IP set ups. Use Modbus TCP/IP to communicate with an unlimited number of devices. Like EtherNet/IP, it is only available with standard devices with the option for a display.
Modbus TCP/IP specifications
- Alicat part number: -MODTCPIP
- Electrical connections: Comms over dual RJ45
- Power over protocol connector: No
- Dedicated power jack: Required
- Additional power requirement: 120 mA
- Device compatibility: Incompatible with CODA, BASIS, EPC, Class 1 Division 2, and portable devices
- Available with display?: Yes
- Available via retrofitting to standard device?: No
- Software compatibility: LabVIEW; Modbus Poll
- Max number of devices on network: No limit
- Topologies: Star; linear
Resources
- Modbus operating bulletin
- Modbus Poll Data Registers – MBP file – This loads the configuration requirements required to read the available data registers on any Modbus-equipped Alicat device and is useful for troubleshooting and viewing the required Modbus data settings.
Limitations
- Incompatible with CODA, BASIS, EPC, Class 1 Division 2, and portable devices.
- No analog signals.
- More expensive than ASCII or Modbus.
- Requires 120 mA power.
PROFIBUS DP-V0
Many Alicat devices are available with PROFIBUS for communication with up to 125 devices. PROFIBUS is an open specification communication standard designed for automation equipment.
PROFIBUS specifications
- Alicat part number: -PROFIBUS
- Secondary protocol: ASCII over RS-232 (primarily for debugging)
- Optional certifications: IP66/67 (requires a minimum quantity order)
- Electrical connections: 9-pin D-sub PROFIBUS connector next to a 4-pin M8 connector for RS-232 communication and power
- Power over protocol connector: Available
- Dedicated power jack: No
- Additional power requirement: 120 mA
- Device compatibility: Incompatible with CODA, BASIS, EPC, Class 1 Division 2, and portable devices
- Available with display?: Yes
- Available via retrofitting to standard device?: No
- Software compatibility: Serial terminals (Alicat Terminal, HyperTerminal, PuTTy); FlowVision 2.0
- Max number of devices on network: 125
- Topologies: Linear with termination resistor
Resources
For instruments built after* July 12, 2020:
For instruments built before July 12, 2020:
*Customers with the GSD file for instruments built prior to July 12, 2020 file may continue using it with new units if your system is already configured.
Limitations
- To communicate with the Alicat, users must have a PROFIBUS card inside of a PC or a PROFIBUS-enabled PLC.
- Incompatible with CODA, BASIS, EPC, Class 1 Division 2, and portable devices.
- Not as fast as analog or ASCII serial communication.
- More expensive than ASCII or Modbus.
- Requires 120 mA power.
PROFINET specifications
- Alicat part number: -PROFINET
- Electrical connections: Dual RJ45
- Power over protocol connector: No
- Dedicated power jack: Required
- Additional power requirement: 75 mA
- Device compatibility: Incompatible with BASIS, EPC, Class 1 Division 2, and portable devices
- Available with display?: Yes
- Available via retrofitting to standard device?: No
- Max number of devices on network: No limit
- Topologies: Star; tree; line; ring
Resources
- PROFINET manual
- PROFINET GSD file for M, L, P series
- PROFINET GSD file for CODA series
- PROFINET Certification for M, L, P series
- PROFINET Certification for CODA series
Limitations
- Requires a PLC.
- Incompatible with BASIS, EPC, Class 1 Division 2, and portable devices.
- No analog I/O.
- More expensive than ASCII or Modbus RTU.
- Requires 75 mA power.