The High-Speed Synchronous Serial Interface (HSSI) provides a simple way to expand and distribute I/Os and other controller interfaces. The controller communicates with the expansion modules through standard Ethernet cables at a maximum length of 20 meters per HSSI channel.

The number of HSSI channels is equal to half the number of axes supported by the control product.

The physical HSSI layer is RS-485. Data is sent to the HSSI remote module/modules and received by the SPii processor at a deterministic rate of 20kHz (every 50 microseconds).


Distributed I/O Expansion Module 16 opto-isolated inputs and 16 opto-isolated outputs for SPiiPlus motion controllers

The HSSI-IO16 Module monitors the HSSI communication channel and its own integrity.If the integrity check fails, the module automatically turns off all outputs.

Every module is manufactured under an ISO9001 certified quality management system and meets stringent safety and EMC standards.

The HSSI-IO16 is a modular I/O expansion unit that provides

•  16 opto-isolated inputs and 16 opto-isolated outputs

•  fully coordinated with motion.

•  Up to 4 units of HSSI-IO16 can be daisy chained via each HSSI channel

•  4 HSSI Channels maximum per controller

•  64 inputs and 63 outputs per channel.

•  256 inputs and 252 outputs can be added by using 16 HSSI-IO16 modules.

•  I/O can be configured as either sink or source in groups of 8

•  Total current available to each group of 8 I/O is up to 350mA.

•  All outputs have overload protection.

•  LED indicates the state of each input and output.

•  Cost effective way to implement a distributed I/O system

•  DIN rail or surface mount


Unit Supply: 24Vdc ( ± 20%). Power ON LED indication.

I/O Supply: External 5Vdc ( ± 10%) or 24Vdc ( ± 20%) - automatically detected. The system 24V supply can be used instead, without isolation.

Inputs: 16. Each with a green LED status indication.

Propagation delay:< 1msecond.

Type: Sink/Source configurable. Opto-isolated.

Outputs: 16. Divided into 2 groups of 8 outputs. Each with a green LED status indication.

Current: Each output can source up to 350mA. Total current per group<350mA. Total current per 16 outputs <700mA.

Propagation delay: < 1msecond.

Type: Source or sink (order dependant). Opto-isolated.

Communication: 2.5MHz. Refresh period: each servo cycle 50 micro seconds.

Green/Red LED for status indication.

Dimensions: H 74mm x W 190mm x D 34.5mm (H 2.91 x W 7.48x D 1.36).

Two-Axis Distributed Interface Module

The HSSI-ED2 module provides a convenient and cost-effective way to interface the SPiiPlus controller with two distributed axes.

With the ED2 performance of the distributed axes is comparable to that of the axes that are connected directly to the controller. The controller samples the remote encoders and updates the drive commands at a rate of 20kHz, providing high-bandwidth servo control, exceptional dynamic tracking, and fast settling time. Another important advantage of the HSSI-ED2 is that the cabling between the distributed axes and the motion control product is reduced to just the single HSSI CAT 5 cable.

The HSSI-ED2 module monitors the HSSI communication channel and its own integrity. If the integrity check fails, the module automatically disables the drives and turns off all the outputs.

•  Two motor drive interfaces with +/-10V torque command,

•  Two 3-channel quadrature (A&B, I)encoder inputs,

•  Four limit switch inputs,

•  General-purpose digital I/O 8 inputs/8 outputs.


The module front panel includes LED indicators for power, communication, drive enable, safety inputs, and each general purpose digital input and output.



Quantity: Two.

Drive Interface

Quantity: Two.

Drive Type: For DC brush or DC brushless motors (commutated by the drive).

Torque Command: ± 10V, differential, 14-bit DAC resolution.

Drive Enable Output: Opto-isolated, open collector/open emitter, 5V to 30V, up to 50mA.

Drive Fault Input: Opto-isolated, source/sink, 5V (+/-10%) or 24V (+/-20%), automatically detected.

Encoder Interface

Encoder Type: Three channel (A&B, I), differential, RS-485.

Maximum Rate: 20 million encoder counts/second.

A, B line cycle: >200nsec.

A, B low & high states: >100nsec.

A-B edge separation: >25nsec.


Type: Opto-isolated, sink/source configurable.

Limit switch: Four (two per axis).

General purpose: Eight.


Type: Opto-isolated, source.

General purpose: Eight.

Total current for all outputs: <350mA.


Power: External 24Vdc ( ± 20%).

I/O: External 5Vdc ( ± 10%) or 24Vdc ( ± 20%),

automatic detection.

LED Indicators

Power on, communication OK, drive fault, drive

enable, each right and left limit, each input and output.


HSSI cable: FTB, category 5 Ethernet-type.

Maximum cable length: 20m (65' 7.4").


74mm (2.91") x 190mm (7.48") x 34.5mm (1.36")

[H x W xD]

HSSI-ED2 Layout and Components