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Connections

Connections

Overview

Connections (also called Ports) facilitate communications between a device protocol and an end-point or field device. Logical ports are defined within ACM to represent a communication method used to connect to a device. Each logical Port has a name that is used to reference it. Whenever a port is used, all of the settings defined by that port are used for communications. Multiple devices and/or multiple device types in ACM can use a single port for communications. 

Choosing TCP Connection Types

Connection Type

Situations

Notes

Connection Type

Situations

Notes

TCP/IP Port

  • Point to Multipoint Serial Radio networks connected via a Terminal Server (multiple devices poll through a shared IP and Port number). 

  • Example: Digi, Moxa, Lantronix Terminal server attached to a multidrop serial network (common example GE/MDS 9810)

  • Hard Wired Ethernet Devices (not going through a shared wireless connection) 

Socket connection can be set to maintain the IP connection, or release when not polling.

TCP/IP Listen

  • Wireless Ethernet Networks with limited and shared bandwidth.  Use a TCP Listen Object for each network segment.  Set the max sessions to a value to prevent ACM from over saturating those networks with data rates they cannot physically handle.  (Example: GE / MDS iNet)

  • Cellular IP Connections

  • Socket connection will only be established when devices are due to poll. 

  • Since the connection is not persistent, this connection type can accept and process inbound IP socket connection requests from field devices to handle RBX messages.  This is commonly done with Sierra Wireless Raven modems (cellular connection).

  • The max sessions option is highly useful for controlling traffic on limited bandwidth shared wireless connections.  Some network segments get flooded with traffic to the point that connections start dropping (WSAEABORTED, etc) when they try to use the standard TCP/IP connection type which can't throttle the number of concurrent connections.

TCP/IP Pool Port

  • Modem Banks – typically a terminal server ( or terminal servers ) with serial modems attached.  This connection enables the most efficient utilization of those modems.  Users don’t have to manage assigning groups of devices to each modem individually.