Key Features:

• Fully isolated between all circuits: Inputs, outputs, alarm, network ports, enclosure, and power are isolated from each other for safety and noise immunity.
• High-density stackable unit: Stacked mounting puts a lot of I/O in a very small footprint to save panel space.
• Modbus TCP/IP or UDP/IP protocol: I/O functions as slave to host controller.
• Peer-to-peer i2o communication: Inputs to one unit automatically actuate outputs on another over Ethernet link.
• Channel-to channel input isolation: Inputs provide high or low-side sensing for AC or DC circuits.
• Automatic change of state detection: Inputs detect quick momentary changes of state that occur between polling.
• Logic inversion (i2o only): Active high inputs can switch remote peer-to-peer outputs on or off.
• Change-of-state or timed updates: Event-driven updates transmit data in less than 10ms between peers with i2o.
• 10 Modbus TCP/IP sockets/sessions: Multiple masters can talk to an EtherStax unit at the same time.
• Local alarm function: Dedicated failsafe relay is controlled via watchdog timer and link-loss conditions.
• Heavy-duty 2A relays: 16 SPST outputs provide high/low-side 2A switching up to 250V AC or 110V DC.
• Programmable outputs: Normally open relays are configurable to energize or de-energize on power-up.
• Built-in slave relays: Inputs can control outputs on same unit to provide slave relay interface.
• Self-test checks I/O operation: Unit checks internal I/O communication and allows verification via web browser.
• Watchdog timers: Communication fault sends output to a pre-defined state or holds the last value.
• Operating Temperature: -40° to +65°C.

Product Details


– 32 individually isolated, buffered inputs grouped in two 16-ch ports. Active-high operation.
Input Voltage Range
– 20-32V DC, 36V DC max.
Max voltage/operating temperature:
– 36V DC @ 65°C max.
Input Signal Threshold and Hysteresis
– OFF-ON: 13V min, 20V max, 16V DC typical.
– ON-OFF: 11V max, 7V min, 9V DC typical.
Input Impedance
– 6k ohms.
Input Isolation:
– Channel-to-channel: 150V AC isolation rating.
– Port-to-port: 250V AC safety isolation rating.
Input Response Time
– Less than 5ms.
Peer-to-peer (i2o) communication
– Change-of-state updates: Less than 10ms events.
– Timed updates: Configurable for 1-90 seconds.


– One 16-ch port of isolated SPST-NO mech. relays.
Maximum Switching Voltage / Load Rating
– 250V AC, 110V DC @ 2A.
Mechanical Life
– 20 million operations minimum.
Electrical Life (@ 20 cycles per minute)
– 100k operations minimum at 2A.
Contact Resistance (Initial)
– 30 milliohms, maximum.
Output Response Time
– Less than 5ms.
Minimum Load
– 100µA/100mV DC.

Local Alarm Output

– Failsafe or non-failsafe (software-configurable) relay trips on power or link-loss failure.
– SPST-NO, 1 Form A, Class I, Division II approved.
Maximum Switching Voltage/Load Rating
– 240V AC, 125V DC @ 2A.
– 100K operations minimum.

Ethernet Interface

Internal Switch or Hub/Repeater
– Dual-port Ethernet switch. Web-configurable as a true switch (default mode) or low-latency hub.
Network Connector [10/100 Base-T(X)Copper]
– One or two 8-pin RJ-45 connectors. Automatic MDI/MDI-X. 100m communication distance.
Network Connector (100 Base-FX Fiber-optic)
– One multi-mode with SC connector. 2km communication distance. Full/half-duplex, selectable.
Protocols and Addressing
– Modbus TCP/IP or UDP/IP. i2o peer-to-peer.
– StaticIP, DHCP, BootP. Configurable IP addresses.
Ethernet Modbus TCP/IP Sockets/Sessions
– 1-10 socket/sessions programmable via web page.
Ethernet Redundancy
– Compatible with STP, RSTP, proprietary schemes.


Operating and Storage Temperature
– Operating: -40 to 65°C.
– Storage: -40 to 85°C (-40 to 185°F).
Power Requirements
– 18-36V DC. Redundant, diode-coupled terminals.
– 4.7W (copper ports), 6.0W (fiber-optic ports).
– I/O, power, relay and Ethernet port-to-port.
– Peak: 1500V AC, ANSI/ISA-82.01-1988.
– Continuous: 250V AC, 354V DC (150V AC ch-ch).

Enclosure and Physical

Safety Approvals (pending)
– CE marked and UL/cUL Listed.
– Hazardous Locations: Class I; Div 2; A, B, C, D.
– Open board units: UL Recognized.
– Shock and Vibration Immunity (in enclosure).
– Mechanical Shock: 50g (3ms), 30g (11ms).
– Random Vibration: 5g, (5-500Hz).