Solid-State and Electromechanical Relay Products

Relay is the name for a switch that is operated electro-mechanically or electronically. Their main task is to make and break connections to control the flow of current in electrical circuits. They’re used for various purposes ranging from validating semiconductors to interfacing low power computers or microcontrollers with high power machinery.

There are two main types of relays. Electromechanical Relays use an inductor to mechanically operate the arm of the switch while Solid State Relays (SSR) have no moving parts but instead use the electrical and optical properties of semiconductors to perform their switching functions. At ACCES I/O we use Field Effect Transistor (FET) switches for non-mechanical solutions as they have faster switching speeds and smaller form factors than traditional SSRs.

In order to choose the right relay for your application it is useful to first take note of the key differences between main types of relays.

In Electromechanical Relays (commonly just relays) the connection is controlled by an arm that opens and closes as a response to the magnetic field induced in the coil on the other side. The mechanical robustness of this connection allows it to operate in harsh conditions and to support a wide range of signals, but that’s also what makes this connection slower (5-15ms) and bulkier. Another important occurrence in Electromechanical Relays resulting from its construction is so called contact bounce that causes a noise after switching the relay position to closed but it can be efficiently cushioned by using a debouncing filter.

FETs (often called high side or low side switches) due to their non-mechanical nature offer zero contact bounce and are much faster (0.5-1ms) and smaller. The common problem with them is that they require a minimum load to work and they can switch only DC signals. They’re recommended whenever faster and more frequent switching is required and are a perfect solution for low noise applications like precise measurements.

For more information about different variants of FETs and Electromechanical Relays and guidance on how to choose the right relay for your application, click here.


PCI Express Bus Relay Products
MODEL DESCRIPTION RoHS
PCIe-IDIO-2448-channel I/O (24 isolated digital inputs, 24 isolated high-side FET switches) with COS (change of state)
PCIe-IIRO-1632-channel I/O (16 isolated digital inputs, 16 electromechanical relay outputs) with COS (change of state)
PCIe-IDIO-1224-channel I/O (12 isolated digital inputs, 12 isolated high-side FET switches) with COS (change of state)
PCIe-IIRO-816-channel I/O (8 isolated digital inputs, 8 electromechanical relay outputs) with COS (change of state)
PCIe-IDI-2424 isolated inputs (24 optically isolated digital inputs) with COS (change of state)
PCIe-IDO-2424 isolated outputs (24 isolated high-side FET switches)
M.2 Bus Solid-State and Electromechanical Relay DAQ Products
Products # I/O Buf Prog OPTOs Relays CTRS COS RoHS
M2-II-16
Coming Soon!
16 InYes Yes  Yes
M2-II-8
Coming Soon!
8 InYes Yes  Yes
M2-II-4
Coming Soon!
4 InYes Yes  Yes
M2-IDIO-8
Coming Soon!
8 In/8 OutYes Yes8SS* Yes
M2-IDO-8
Coming Soon!
8 OutYes  8SS*  
M2-IDIO-4
Coming Soon!
4 In/4 OutYes Yes4SS* Yes
M2-IIRO-8
Coming Soon!
8 In/8 OutYes Yes8 Yes
M2-RO-8
Coming Soon!
8 OutYes  8 
M2-IIRO-4
Coming Soon!
4 In/4 OutYes Yes4 Yes
Buf = Buffered I/O   Prog = Programmable I/O   OPTOs = Optically Isolated   * Solid State
CTRS = Counters/Timers   COS = Change Of State Detection   = Optionally available RoHS Ready
PC/104 Solid-State and Electromechanical Relay Products
MODEL DESCRIPTION RoHS
104-IIRO-824-channel (8 isolated digital inputs, 8 TTL inputs, 8 relay outputs) with change of state detection
104-IIRO-8E24-channel (8 isolated digital inputs, 8 TTL inputs, 8 relay outputs) without change of state detection
104-IIRO-1632-channel (16 isolated digital inputs, 16 relay outputs) with change of state detection
104-IIRO-16E32-channel (16 isolated digital inputs, 16 relay outputs) without change of state detection
104-II32-4RO32 isolated digital inputs and 4 relay outputs with change of state detection
104-RO-1616 relay outputs only version
104-IDIO-1632-channel (16 isolated digital inputs, 16 solid state outputs) with change of state detection
104-IDIO-16E32-channel (16 isolated digital inputs, 16 solid state outputs) without change of state detection
104-IDIO-816-channel (8 isolated digital inputs, 8 solid state outputs) with change of state detection
104-IDIO-8E16-channel (8 isolated digital inputs, 8 solid state outputs) without change of state detection
104-IDO-1616 isolated digital outputs only version
104-IDO-88 isolated digital outputs only version

PCI and Low-Profile PCI Solid-State and Electromechanical Relay Products
MODEL DESCRIPTION RoHS
PCI-IIRO-8Eight isolated digital inputs and eight relay outputs card
LPCI-IIRO-8Low profile, eight isolated digital inputs and eight relay outputs card
PCI-IIRO-16Sixteen isolated digital inputs and sixteen relay outputs card
PCI-IDIO-16Sixteen isolated digital inputs and sixteen FET outputs card
PCI-IDO-1616-channel individually optically isolated solid state digital outputs
PCI-IDO-3232-channel individually optically isolated solid state digital outputs
PCI-IDO-4848-channel individually optically isolated solid state digital outputs

USB and USB/104 Solid-State and Electromechanical Relay Products
MODEL DESCRIPTION RoHS
USB-IDIO-16 USB to 16 optically isolated digital inputs (AC or DC) and 16 isolated solid-state relay outputs
USB-IDO-16 USB to 16 isolated solid-state relay outputs only
USB-IDIO-8 USB to 8 optically isolated digital inputs (AC or DC) and 8 isolated solid-state relay outputs
USB-IDIO-16LUSB to 16 optically isolated digital inputs (AC or DC) and 16 isolated low-side solid-state relay outputs
USB-IDO-16LUSB to 16 isolated low-side solid-state relay outputs
USB-IDIO-8LUSB to 8 optically isolated digital inputs (AC or DC) and 8 isolated low-side solid-state relay outputs
USB-IIRO-4 USB to 4 optically isolated digital inputs (AC or DC) and 4 electronmechanical relay outputs
USB-IIRO4-2SM Small USB-based unit provides 4 optically isolated inputs and 4 electromechanical relay outputs, as well as 2 RS-232/422/485 Serial Ports
USB-IIRO4-DB USB to 4 optically isolated digital inputs (AC or DC) and 4 electromechanical relay outputs with external DB25 connector
USB-IIRO-8 USB to 8 optically isolated digital inputs (AC or DC) and 8 electromechanical relay outputs
USB-RO-16 USB to 16 electromechanical relay outputs
USB-IIRO-16 USB to 16 optically isolated inputs (AC or DC) and 16 electromechanical relay outputs in a small, rugged steel enclosure
USBP-DAQ-2AI-1EM
In Development!
Standalone or USB logging module with 2 16-bit analog inputs (you pick the input ranges!) and 1 electromechanical relay output. Log data for hours or months, with configurable alarm thresholds.

Wireless Relay Products
MODEL DESCRIPTION
WM-IIRO-8 8-Channel optically isolated input / electromechanical relayt output module.
WWP-IIRO-8 A unique automated solution to wirelessly transmit the state of 8 isolated inputs up to 7 miles to 8 corresponding relay outputs -- bidirectionally, with no computer involved!

Signal Conditioning Solid-State and Electromechanical Relay Products
MODEL DESCRIPTION RoHS
ROB-8A 8-Port Electromechanical Relay Card
ROB-24 24-Port Electromechanical Relay Card
ROB-24H 24-Port Electromechanical Relay Card, High Current Rating (For add-on options, see ROB-24)
A16A Solid-state I/O Modules and Cards
A24A Solid-state I/O Modules and Cards
Acquisition, Control, Communication: Engineering and Systems

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