COMMUNICATION OPTIONS
SNAP PAC R-Series Controller User’s Guide
18
•
Custom software applications
are easy to develop using our OptoMMP
Communication Toolkit with ActiveX components and C++ classes. They use an IEEE
1394-based protocol to read and write to SNAP PAC R-series controllers. For developers
not using Microsoft Windows, our IEEE 1394-based protocol is open and documented.
•
EtherNet/IP
provides communication with Allen-Bradley ControlLogix® and
CompactLogix™ PLC systems and other systems using the EtherNet/IP protocol. Both
implicit and explicit messaging are supported.
•
Modbus/TCP
provides a direct connection with Modbus/TCP hardware or software or
third-party software applications, which can read or write to I/O points on SNAP PAC
R-series controllers.
•
OPC
(OLE for Process Control) uses OptoOPCServer to serve controller data to any OPC
2.0-compliant application, such as an HMI, which can also read or write to I/O points.
OptoOPCServer can be purchased separately or as part of the PAC Project Professional
software suite.
•
SMTP
(Simple Mail Transfer Protocol) connects a SNAP PAC R-series controller with
corporate email servers, so employees can be emailed or paged if there’s a problem on
devices attached to the controller.
•
SNMP
(Simple Network Management Protocol) makes it possible to monitor devices
attached to SNAP PAC R-series controllers just as you would any computer or server on
the Ethernet network, using an SNMP-based enterprise management system such as
Computer Associates’ Unicenter
®
, Hewlett-Packard’s OpenView
®
, or IBM’s Tivoli
®
. When
a monitored event occurs, such as a door left open or a pressure level too high, the
controller sends an SNMP trap to the management system.
•
FTP
(File Transfer Protocol) can be used to transfer files and data to and from the SNAP
PAC R-series controller, whether to custom applications, enterprise databases, or any
file system. R-series controllers manufactured after November 2008 include removable
storage capability: a MicroSD card slot that accommodates cards up to 2 GB. See
page 50
for information on using the card for storage and for loading firmware or PAC
Control strategies to the controller.
Simultaneous Communication
In addition to communicating using all the methods listed above, each SNAP PAC R-series
controller can also communicate
simultaneously
using all applicable methods.
The reason lies in the nature of IP. In serial communication, a single data request is sent by
one device to another. The first device must wait for a response before any additional
communication can be carried out. IP, however, can establish multiple simultaneous
sessions, so many data requests can be sent at once without waiting for any individual
response. Each request gets a response, but the link isn’t idle while waiting for responses.
In addition, IP can simultaneously handle multiple requests from multiple devices. A PC can
communicate with all SNAP PAC R-series controllers on the same network—all at the same
time—and multiple PCs can communicate with one controller at the same time.
