(714) 979-7893
Email: info@able.com

SCSIserver ^TM Real Time Application

A Unix platform is running a railway switching system in Texas. The switches are connected with multi-drop modems with a backup microwave transceiver that can be polled if the modem or telephone line goes down.

PROBLEM: The processor needs help - it can't maintain "real time" with the burden of controlling modem lines for half-duplex multi-drop protocols and screening out squelch noise from microwave reception. Terminal servers weren't usable and the customer could find no embedded controller solution that could give them the needed performance.

SOLUTION: The SCSIserver supports half-duplex protocol locally freeing the processor. In addition, working with the customer ABLE added an additional simplex mode for the microwave ports - by adding a user selectable timer for masking out incoming squelch noise and for delaying output data transmission for a time after microwave keying.

Up to 32 switch boxes are controlled from each port of a SCSIserver using multi-drop modems. A half-duplex protocol is used for gathering and sending data to the boxes for control. A backup function is being handled by microwave for modems that don't respond because of telephone or hardware failure.

When the microwave is keyed, noise is generated for a measurable period of time. ABLE added a timer to its simplex mode to allow masking of squelch noise on input and to delay output data transmission on output after microwave keying.

The processor has to pole and take action from all ports in less than 2 second. A train can travel almost 60 yards at 60 mph. The customer said that without SCSIserver the time requirement could not have been met. As it was, they bettered it with more than adequate margin.

Another Site that shows
WE'RE NOT ONLY WILLING -
WE'RE
ABLE

Home | Company | Product | Applications | Tutorials | News | FAQ