SmarTek Systems SAS-1 Communication Via Internet - Manual (Page 3)

SmarTek Systems (www.smarteksys.com) 3
Detailed Protocol/Formats for Multiple Device Communication
This document describes the communication protocol/format between data collection software
running at a central facility and a roadside cabinet with multiple SmarTek SAS-1 traffic sensors and
a SmarTek Cabinet Watchdog Voltage Monitor. Connectivity between the central facility and all
roadside cabinets may be a network or the internet.
Each cabinet may be connected to one or more SAS-1 traffic sensors (SAS0001, SAS0002, etc.) and
a Cabinet Watchdog Voltage Monitor. Each of these devices must be set during installation to
operate in the polled mode since they all share a common serial communication line to the system
interface (CDPD modem, serial device server, dialup modem, etc.). This interface implements the
communication link back to the central facility.
The following section describes the required polling command which is sent to each cabinet and the
resulting data message response format from each device connected to the system interface in the
roadside cabinet. The response order is also shown.
This protocol description applies to SAS-1 software Version SAS_140 or later.
Global Broadcast Command To Each Roadside Cabinet:
<ESC>{SAS0000,FLOW=Chr(33),Mess_Format}
Mess_Format = Chr(33) for Simple Flow, Chr(34) for Flow with Truck Count
ASCII Chr(33) is ! and Chr(34) is “
<ESC> is ASCII Chr(27)
Example:
<ESC>{SAS0000,FLOW=!,!} (Poll Command: Simple Flow Message)
or
<ESC>{SAS0000,FLOW=!,”} (Poll Command: Message with Truck Count)
Response from Roadside Cabinet (SAS-1s and Cabinet Watchdog)
For Mess_Format=Chr(33):
First:
Chr(2)CWD0001<sp>aa.aaa<sp>bb.bbb<sp>cc.ccc<sp>dd.ddd<sp>efghijkl<CR><LF>Chr(3)