EthernetIPforCLXCom

EthernetIPforCLXCom

This driver specifically targets the Allen Bradley line of ControlLogix and CompactLogix PLCs. It uses tag names directly to access data values in the PLC.

Properties
IPAddress	The TCP/IP address of the PLC to communicate with
Port	The TCP/IP port. In nearly all cases this will be 44818
CIPConnectionSize	The maximum number of bytes in a single packet. The larger the number, the more efficient the communications. A value of 508 works with all Allen Bradley PLCs tested. Some of the newer models will allow a higher value.
DisableMultiServiceRequest	A multi-service request allows more than one request per packet. This can dramatically increase the speed of retrirving values. Not all PLCs support this, such as the Micro800 series.
DisableSubscriptions	uses updating of subscriptions. This is useful in cases such as when hiding a form and there is no longer a need to refresh the values. Or when used with a Trend Chart, it can pause the charting.
PollRateOverride	This set the target rate for refreshing all of the subscriptions. When there are a large number of subscriptions that have to be split amongst sever requests, this value is divided by the number of requests required to determine the delay between each packet. A value of 0 will make the driver update as fast as the PLC will respond, but be cautious because it can reach rates less than 5ms and start to use a lot of resources.
INIFileName	An INI file can be created to store the properties for being set during application startup. See INI File Usage for more details
INIFileSection	Specifies the section within the INI file to use for this driver instance settings
RoutePath	Used to specify routing through ControlLogix chassis. Explained in more detail on the Routing Paths page

Methods

For the methods common to all drivers see the section on the IComComponent

GetTagList() - Returns the list of controller scope and program scope tags. This is a synschronous method and can delay for a long time when reading a program with a very large tag list.

BeginReadMultiple(taglist() as string) - A very efficient way of reading multiple mixed tags.

WriteUDT(TagName as string, Value as Object) - Used to write all data to a UDT in a single call and as few packets as possible.

ReadUDT(Of ObjectType)(TagName as string, NumberOfElements as Integer) Reads a complete UDT and creates a .NET object to hold the data

Addressing

Controller scope tags are addressed by directly using the tag name. For example:

MyTag

Program scope tags require a prefix to indicate which program. For example:

PROGRAM:MainRoutine.MyTag

UDT elements are read by specifying the UDT variable. For example:

MyUDTTag.Element

Code Samples

'* Synchronous read of a single tag
'* This is the simplest way to read a tag, however it does block the UI thread until the data is returned
Dim MyDriver as New EthernetIPForCLXCom
MyDriver.IPAddress="192.168.0.10"
Dim MyValue as String
MyValue=MyDriver.Read("MyTag")