DOT Easily Adds VMS to Existing Network
The Department of Transportation (DOT) in a large metropolitan city was
already using Perle Device Servers in order to Ethernet enable traffic
controllers. The DOT began using Perle IOLAN Device Servers (DS)
several years ago, to incorporate video surveillance technology at
intersections. Perle IOLANs had allowed them to maintain the use of existing
traffic controllers when they upgraded the network to a bandwidth for new
video technology. At that time, the DOT was not only able to avoid new
hardwiring and associated construction costs, but also the costs of replacing
controllers that had not reached the end of their useful life.
Now the IOLAN Device Servers would be used for yet another essential function.
Electronic Variable Message Signs (VMS) have become a familiar sight
on the arterial roads throughout many countries. VMS provide traffic
management professionals with a reliable, fast, and effective means
of communicating important traffic information to motorists. A wide range
of details such as road conditions ahead, travel times, road construction
details, accident information and AMBER Alert messages, can be displayed
- all in real-time. This information, when relayed to motorists helps
to reduce congestion and keep traffic moving efficiently and safely.
On the advice of a Traffic Consultant, the system had been configured
with the scalability to accommodate future expansion. Now that
the area required a VMS, it was easily connected; especially with
Perle’s universal, software selectable EIA/RS232/422/485
serial port interface. This Perle advantage means that a single
multiport IOLAN unit can support RS232/422/485 connection types
in a software configurable per port setup. This eliminates the
requirement for multiple device servers for each of the RS232/422/485
devices. With Perle’s software control for RS232/422/485
the potential for failure as a result of someone inadvertently
flipping a switch is eliminated. Any serial device can be connected
back to the Traffic Control Center (TCC) application in a TCP/IP
format or converted back to serial format at the TCC depending
on the application server’s requirement. Pavement sensors,
PTZ cameras, vehicle counters, traffic controllers, or in this
case – variable message signs - are easily and economically
added. Perle IOLANs offer a wide range of 1-48 ports for maximum
scalability and expansion.
Perle IOLANs are designed specifically to meet the rapid polling environments found in traffic management
systems. With its 87 MIP processor, IOLANs have the lowest latency of any serial to Ethernet conversion
product on the market. Flexibility and high performance IP technology, make the IOLAN ideal for critical ITS
applications that require an efficient way of communicating with serial devices over a network. Initially, at the
testing stage of this project, several Perle competitors failed to meet the stringent low latency solution requirements
set by the DOT. Traffic control professionals that have to ensure safe and efficient surface transportation depend
on the reliability of Perle IOLAN Device Servers.
Perle IOLAN Serial to Ethernet for ITS
- Low packet latency of 2 ms
- Meets NTCIP specifications
- IOLAN
SDS1-T, SDS2-T and SDS4-T models all meet NEMA 170 temperature range
specifications
- High performance processors in the IOLAN STS8 (400
MIPS) and SDS1 T (87 MIPS)
- Universal software selectable RS232/422/485
serial ports
- Wide choice of RS232 serial port interface models – DB9M,
DB25M, DB25F and RJ45
- Serial packet data control – fine
tune how serial data is forwarded across an Ethernet network
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