USB Relay Control

Simple USB Connection
Mounts as a Virtual COM Port
Computer Control Through the USB Port

USB Relay Control

USB Relay ControlOur USB ProXR Series Relay Controllers make it easier than ever to add computer controlled switching to your most demanding computer control applications.  Simply connect to your computer and this controller mounts as a Virtual COM Port on your PC, allowing easy programming from any language that supports serial communications.

Mounts as a COM Port

This ProXR series controller connects to the USB port of your computer and will mount as a COM port on your PC.  USB Drivers will most likely be needed and can be found in the resources section to the right and will also be available in the Base Station Software.  Once powered up, the controller waits for a command.  A command consists of a few bytes of data in numerical format usually between 2 and 6 bytes.  Once the command has been received, the controller processes the command, and sends you back ASCII character code 85 to signal the completion of your command.

ZUSB ModulesUSB Relay ZUSB Module

This board is equipped with a ZUSB Module.  The ZUSB communications module adds USB communications to the board.  The ZUSB module is powered from the USB port of your computer and includes a 6' USB Cable.  The board itself will require 12 volts of power and can be hard wired or you can purchase a "wall wart" type transformer at checkout.

12 Volt DC Powered

While the USB module is powered y the USB port the Board itself requires a +12VDC power supply.  USB specification prohibits relay controllers from being USB bus powered due to surge currents.   We do not sell a mechanical relay controller that is USB bus powered, Please be cautious of any manufacturer who offers such a device.

Sending Commands

Base Station Software is available at no charge to get you up and running fast (more on Base Station below).  Once powered up, the controller waits for a ProXR command.  A command consists of a few bytes of data in numerical format (see full command set) usually between 2 and 6 bytes.  Once the command has been received, the controller processes the command, and sends you back ASCII character code 85 to signal the completion of your command.  If a command was sent to read the status of the relay the status is sent back.

Induction Capacitors

Induction CapacitorPerhaps the most overlooked aspect of relay control is proper handling of inductive loads. Inductive loads can best be defined as anything with a magnetic coil, such as a motor, solenoid, or a transformer.  Controlling a inductive load using this relay controller requires the use of induction suppression capacitors.  The purpose of this capacitor is to absorb the high voltages generated by inductive loads, blocking them from the contacts of the relay.  Without this capacitor, the lifespan of the relay will be greatly reduced.  Induction can be so severe that it electrically interferes with the microprocessor logic of our controllers, causing relay banks to shut themselves down unexpectedly.  In the case of USB devices, customers may experience loss of communications until the device is reconnected to the USB port.  Capacitors that we offer are available at checkout, for more information view our Induction Suppression Video.

Induction Solutions

Even with capacitors in place, the possibility does exist that capacitors will not suppress enough induction to prevent periodic communications loss. Testing is required in these applications. If problems persist, other communications mechanisms must be considered.  If USB is required, an RS-232 communications module will allow RS-232 communications between your PC and controller with no complications.  A USB to RS-232 adapter can be used in combination with the RS-232 controller. The RS-232 communications format effectively blocks induction to safe levels for a USB to RS-232 adapter to function without errors (look for "RS232 Relays" under Shop by Interface on the left navigation).  If the problem persists after you purchase a USB board you can change out the USB module for an RS-232 or wireless module easily.