Physicians in many hospitals and cancer treatment centers use the TomoTherapy Hi-Art System® that is designed and manufactured by TomoTherapy Inc. in Madison, Wisconsin. Engineers at TomoTherapy use Ethernet as the control and communications network for the system.
To provide reliable communications between the main components, the engineers wanted an industrial Ethernet switch that had quick throughput, enhanced reliability, the met the space integration requirements. TomoTherapy chose Contemporary Controls' BAS switch, offering the newest in communication technology. The BAS switch (EIBA5-100T) is designed with a minimum number of components, packing more functionality and ease of installation into this compact device.
Tim Holzmann, Lead Design Engineer for TomoTherapy, says the BAS switch is only accessible to service personnel. It's under the fiberglass covers of the machine, mounted on the rotating gantry. The equipment resembles a CT machine, approximately 12" x 12" x 8" with a steel frame underneath. The two embedded computers on the machine's rotating side are connected to the stationary computers using the BAS switch.
"We were concerned about the small panel area (10 x 6) for mounting," explains Holzmann. "But the BAS switch allowed us to provide secure mounting on the rotating gantry with screw terminal positive locking power connectors. Good mounting holes. No need for receptacles or extension cords or duct tape. We had available low-voltage DC power for easy connection to the switch., saved on extra wiring expense."
"What's even more unique to us," added Holzmann, "is that the label on this switch can be written upon so that port connections can be documented as to the location of our other connected equipment."
The BAS switch is Plug and Play (PnP) with no operator intervention required. In case the power must be removed and reapplied, the unit is able to return to operation. As for regulatory standards, the BAS switch is UL 508 Listed, C-UL Listed, CSA No. 22.2 14-M91, Industrial Control Equipment and carries the CE Mark to be sold in the European Union. The infrastructure is not complicated. Holzmann says the two embedded computers and one RS-485 to Ethernet converter connect to the BAS switch. The computers use either 10 or 100 base communications with the switch. The switch connects to a media converter (CAT 5 to coaxial), across the slip ring, to another media converter, to the stationary machine network. Cable lengths are short, either 2 to 3 feet. There was no need for additional wiring.
The BAS switch met the demands of the embedded medial imaging field. "The switch is operating great," said Holzmann. "We have experienced no failures."
