PC Remote I/O Family Overview

COMMUNICATION CONNECTIONS

Connecting the PC to the Remote Family of interfaces is simple. A single 4-wire serial RS422 cable is daisy-chained from the PC to each interface. Up to 63 interfaces of any combination of functions can be connected to a single RS422 channel. The PC could use a RS422 converter on its RS232 comm port or add a RS422 interface card.


POWER CONNECTIONS

Each interface contains an on-board switching power regulator. Therefore, a higher voltage can be daisy-chained to the remote interfaces keeping the current requirements low and the remote voltages stable. For example, if all the interfaces combined used 10 amps at 5 volts (50 watts), then the current required from a 24vdc supply would be 2.45 amps (58.8 watts) for 85% efficiency. Wire sizes are smaller and voltage variations are not a problem.


REMOTE INTERFACES

Each remote interface has a special wiring base and plug-in logic module. The DIN rail mounted wiring base contains the necessary touch-safe terminal strips along with the necessary jumpers to select address and optional features. The active components are contained in the logic module. The logic module plugs into the screw-down connector on the wiring base. No jumpers or adjustments are needed on the logic module. This makes field replacement easy and safe. Simply remove the module and insert a new one. No wires need to be removed and no jumpers or adjustments need to be done.


SPEED

The 115.2 KBAUD communication rate and simplified protocol make data transfer fast. Typically, 5 bytes are required to request (or send) data to an interface. Since no gaps or filler bytes are needed between different interface addresses, the average time per interface is 5 bytes or 434 usec.

A 10-module system could be continually updated every 4.34 milliseconds. Critical data could be addressed in an interleave fashion, or a second dedicated RS422 port could be used.




Remote I/O | Remote Encoder Input | Remote Analog Input | Remote Analog Output | Remote Stepper Output

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Phocus Systems Inc.
P.O. Box 16160
Seattle, Washington 98116
Tel: (206) 972-0931
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