This driver is used for communication with Allen Bradley
PLCs manufactured by Rockwell Automation
company using the EtherNetIP/CIP
protocol. See also Communication with Allen Bradley PLC devices from the Rockwell Automation company
protocol (Common Industrial Protocol
) is a network protocol that allows to transmit values of data objects. Contrary to other protocols, that are usually oriented to support registers, inputs, outputs, etc., the CIP
protocol is oriented to support data objects. The data object is representing an user-defined data variable, array, structure, etc. that describes some part of the technology and its instances are located in the PLC memory.
The CIP protocol can be implemented on different physical layers (Ethernet, CAN/DeviceNet, FieldBus/ControlNet). The EtherNet/IP protocol implements (encapsulates) the CIP protocol for Ethernet. The PmABradleyCIP driver implements the CIP protocol into the EtherNet/IP protocol.
The PLCs that are based on data areas (DataFile, for example the Input, Output, Integer type ..) cannot communicate by the CIP protocol (e.g. PLC MicroLogix). For such devices the PmABradleyDF1 communication driver is designed.
protocol is supported by following families of Allen Bradley
PLCs manufactured by the Rockwell Automation
Before using this driver in the PROMOTIC application it is highly recommended to read the chapter: Communication using the PROMOTIC drivers
Basic properties of the driver
- Using this driver is bound to purchase the license: PmABradley
. With the freeware version PmFree
, or when developing the application (with development environment
for tersting purposes), this component is always functional.
- The communication is done via Ethernet.
- The PROMOTIC application is the MASTER (i.e. it initiates the data transfer) from this communication point of view.
- The driver is incorporated into the PROMOTIC system by means of the PmComm
The driver supports to usage of PmCommData object (for read and write the variables from/into the PLC). The PmCommMsg object is used only for special auxiliary message that detects the variable names that can be read from the PLC (see further).
For easy integration of this driver into the application it is handy to use: Preconfigurations in group "Allen Bradley PLC"
- The driver has been tested with PAC Allen-Bradley CompactLogix of the 5000 series with the 20 firmware. The driver may malfunction with devices using older versions of the firmware.
The driver supports the following data types:
: is represented by 1 bit in the PLC In the PROMOTIC application represented by the data type: Boolean
: 8-bit signed integer in the PLC. In the PROMOTIC application represented by the data type: Integer
: 16-bit signed integer in the PLC. In the PROMOTIC application represented by the data type: Integer
: 32-bit signed integer in the PLC. In the PROMOTIC application represented by the data type: Long
: 64-bit signed integer in the PLC. In the PROMOTIC application represented by the data type: Double
: 32-bit real number (float) in the PLC. In the PROMOTIC application represented by the data type: Single
: 32-bit array (usually a host are for variables of the BOOL
type) in the PLC. In the PROMOTIC application represented by the data type: Long
: a structure containing the lenght (DINT
type) and a character array (SINT
type) in the PLC. Represents a text. In the PROMOTIC application represented by the data type: String
The variables (so called tags) are created during the PLC programming. The creation of variables means defining their data type, array dimensions and definig the items of the structure, naming the variable and naming the structure. The designer of PROMOTIC application then works with the previously defined names. The variable names are usually called symbols (in this protocol) and the data structures are called templates. The templates can be user-defined, or can be taken from the libraries of the PLC programming tools that support the CIP
Recommended parameters values:
|TCP/UDP port number||44818|
|Ethernet transfer type||TCP|
Description and recommended values for the Protocol parameters:
|port number in the PLC||1 (set the linkup to documentation)|
|slot number in the PLC||0, position number in rack (set the linkup to documentation)|
|ticks priority||5 (set the linkup to documentation)|
|number of ticks to timeout||247 (set the linkup to documentation)|
The communication description by the PmCommData objects
The variables in the PmCommData
object (or even better the variables in the PmData
object with ExtComm
data extension) can be of arbitrary number, type and order. The driver uses optimalised internal communication messages for reading the data from the device.
All variables are read (if the Data refresh enabled configurator is enabled). When writing to the variable, only the single value is sent (if the Auto send when writing to item configurator is enabled).
Description of the ItemID configurator:
ItemId is the text identifier of the item that is used for addressing the value in the device. The ItemID configurator tells the driver how to receive or send the item value. The text can be written manually, or it can be assembled in the window opened by the button to the right of the configurator. Macro expression can be used for input (it is evaluated while the application is launching).
Entering the ItemId by the button to the right of the configurator is possible only if the file fith PLC variables descriptio already exists. This file can be created by the PmCommMsg mesage ("Reading names of all available variables from the PLC") - see further.
The period (.) separator is used between the structure name and structure item. The array indexes (zero-based index) are written inside the brackets ([ ]). No additional spaces are allowed.
Examples of identifier syntax:
1) In the PLC, there is an elementary item (e.g. of the INT
type) named "Temperature"
. If we want to read/write this item then the ItemId
2) In the PLC, there is a structure named "station"
and inside it there is an array named "data"
. If we want to read/write the 23rd item of this array then the ItemId
3) In thee PLC, there is a "heating"
structure, containing "Boiler"
array. Each item of this array is a structure containing "Temperature"
item. We want to read/write from/into the 0. (i.e. the first position) item of the array:
4) In the PLC, ther is a 3-dimensional array named "warehouse"
and we want to read/write the value on the coordinate of [12,11,5]:
5) Reading and writing a string
: In the PLC, there is a structure named "label"
containing an aitem of the DINT
type (text lenght) and an array of characters of the SINT
type. This structure may represent text and if we want to read/write such text, then the ItemId
This configurator is not used for given driver.
The communication description by the PmCommMsg objects
obejcts can be used for special communications, that cannot be executed by the PmCommData
object. For this driver, there is only a singe special message implemented:
- Reading names of all available variables from the PLC
In order to set the ItemId configurator correctly in the variables for the PmCommData object it is necessary to know the names of user-defined variables, items and structures or array dimensions in the PLC. This informaton can be read from the PLC and this is exactly the sole purpose of this message:
The message reads the information and saves it into a text string on the Data-received page. If the text is saved into a file (default file name is "ABradleyVarCfg.txt") then it is possible to use the button on the right side in the ItemId configurator that reads the corresponding file and displays it in the form of a tree structure. The specific data items can be selected from this tree structure.
In order to create and configure the PmCommMsg object correctly it is recommended to use the Preconfiguration "PmABradleyCIP - Communication set with data and panel by protocol EtherNetIP/CIP (for ControlLogix, CompactLogix, ...)" preconfiguration. If you check the "Create PmCommMsg for reading the variables from the PLC" configurator in this preconfiguration then the correctly configured PmCommMsg object is created together with a panel that can run the message and read the desired information from the PLC. In the onEndOfTransfer event of this object, there is a script that saves the received text information into a file "ABradleyVarCfg.txt".
There are following variables on the Data-received
InfoVars - This variable is used for saving text information regarding available PLC variables.