BACnet/IP to ARCNET Router

Overall Specifications:

• Power: 12VDC at under 50W
• Operating temperatures: 0 to 40ºC
• Storage temperature: -20 to 80ºC
• Relative Humidity: 10-95% non condensing

Ethernet:

• IEEE 802.3 10/100 MBPS
• 10BaseT, 100BASETX phsyical. RJ45 connectors
• Half/Full duplex
• 100m (max) CAT5 cable length.
• LEDs: link and activity as labelled.

ARCNET:

• ANSI/ASHARE 135 (ISO 16484-5)
• 2.5 MBPS data rate
• RG-62 93Ohm coaxial bus physical layer
• 1200m (abs max) cable length
  (Rule of thumb: nodes x km length x termination and dielectric flaws should not exceed three)
• LEDs: link and activity as labelled.

Regulatory Compliance: FCC and CE marked

Options:

• Rack mounting kit.
• External network surge protector.

Connecting BACnet ARCNET network and a BACnet/IP network

BACnet has the same protocol for the monitoring, automation and field levels. It is unified top to bottom. BACnet field controllers with direct I/O and application specific features (B-ASC) can communicate all the way up to BACnet/IP Operator Workstations (B-OWS) and BACnet Building Controllers (B-BC).

In order to interconnect such levels, a BACnet Router is needed. The Cimetrics BR2-A is such a BACnet Router. For BACnet/IP the interface is 10/100 Half/Full Duplex RJ45 standard Ethernet station-side. The ARCNET side is 2.5 Mbps using standard 93 Ohm RG62U coaxial cable.

The BACnet/IP port on the BR2-A connects to the network Ethernet/TCPIP port using a standard CAT5 cable. The ARCNET port connects to the target BACnet ARCNET LAN (93 Ohm RG62U Coaxial cable . The BR2-A can be powered from any 120VAC source. The BR2-A is setup using its embedded webpages.

The ARCNET LAN must have a BACnet Network Number unique from the BACnet Network Number assigned to the BACnet/IP network connection. Nothing precludes the use of multiple BR2-A routers in the same ARCNET network as long as unique BACnet network (and ARCNET LAN MAC) assignments are made for each created BACnet/IP configuration access network.

Bridging BACnet Automation and Field Levels with Multiple Routers

Multiple BACnet Routers can reside within the same BACnet internetwork. A group of ARCNET devices located along an ARCNET LAN, spread in any fashion which adheres to the ARCNET cabling rules, can be bridged to a BACnet/IP network with a BACnet Router. So too can any others like ARCNET, MSTP (or any supported BACnet datalink) be attached using another BACnet Router.

This means of extension is often better than extending existing ARCNET (or MSTP) networks using repeaters. It can also help alleviate LAN loading problems with token collisions, node numbers and cable lengths.

The BACnet/IP port on the BR2-A connects to the main network Ethernet/TCPIP port using a standard CAT5 cable. The ARCNET port connects to the target BACnet ARCNET LAN (93 Ohm RG62 Coaxial cable). The BR2-A can be powered from any 120VAC source. The BR2-A is setup using its embedded webpages.

The ARCNET LAN must have a BACnet Network Number unique from the BACnet Network Number assigned to the BACnet/IP network connection. Nothing precludes the use of multiple BR2-A routers ion the same ARCNET network as long as unique BACnet network (and ARCNET LAN MAC) assignments are made for each created BACnet/IP configuration access network.

Commissioning a BACnet ARCNET device using a BACnet/IP Laptop or other Commissioning Computer

To commission BACnet ARCNET devices one has generally been forced to use a special PC hardware ARCNET interface to communicate with the ARCNET RS485 or Coaxial LAN. The secret is that most BACnet ARCNET software can be run against BACnet/IP and communicate via BACnet Routing to BACnet ARCNET to achieve this configuration/setup connectivity. The Cimetrics BR2-A can accomplish this connectivity. The BACnet/IP port on the BR2-A connects to the PC’s Ethernet/TCPIP port using a standard CAT5 cable. The ARCNET port connects to the target BACnet ARCNET LAN (93 Ohm RG62 Coaxial cable). The BR-A can be powered from any 120VAC source.

The BR2-A is setup using its embedded webpages. The baud rate of the BACnet ARCNET port is setup to match the baud rate and network number of the existing ARCNET LAN.

The ARCNET LAN must have a BACnet Network Number unique from the BACnet Network Number assigned to the BACnet/IP network connection created by the PC connection. Nothing precludes the use of multiple BR2-A routers ion the same ARCNET network as long as unique BACnet network (and ARCNET LAN MAC) assignments are made for each created BACnet/IP configuration access network.