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Allen-Bradley DF1 Full Duplex communication protocol

Supported device types and versions
Communication line configuration
Communication station configuration
I/O tag configuration
Literature
Changes and modifications
Document revisions
The recommended settings of the 1770-KF3 device

Supported device types and versions


The Allen-Bradley DF1 Full Duplex protocol supports communication with Allen-Bradley devices of the SLC-500 series. Communication supports (is verified for) for the following devices:

Table 1

Device typeMeaningProtocol version
Allen-Bradley SLC 5/04Communication with the SLC 5/04 CPU via RS232 port-
Allen-Bradley 1770-KF3DH-485 bus concentrator supports communication with all the devices of the SLC-500 series (description of the setting is mentioned at the end of the chapter).-

Communication line configuration


  • Communication line category: Serial, SerialOverUDP Device Redundant.
  • Serial line parameters:
    • Baud rate (for 1770-KF3, 300, 600, 1200, 2400, 4800, 9600 or 19200 Baud can be used - parameter 3 of KF3 settings - RS-232C Baud Rate),
    • Parity (for 1770-KF3, None or Even parity can be used - parameter 4 of KF3 setting - RS-232C Parity),
    • Handshaking (for 1770-KF3, set the parameter 7 of KF3 setting - Flow Control, according to the setting of the RS-232 cable).


Line protocol parameters

Configuration dialog box - tab Parameters, select the Allen-Bradley DF1 Full Duplex protocol.
They influence some optional parameters of the protocol.

Table 2

ParameterMeaningUnitDefault value
BCC/CRC Checksum
Type of checksum for securing of the payload. CRC
BCC
CRC
Full Debug
Activates detailed listings about sending and receiving values and further debug information.YES/NONO

Communication station configuration


Communication protocol: Allen-Bradley DF1
Station address: DH-485 Node Address of device in the range of 1 up to 31.


Station protocol parameters

Communication station - configuration dialog box - the Protocol parameter input field.
They influence some optional parameters of the protocol.

Table 3

ParameterMeaningUnitDefault value
Interface Node
DH-485 Node Address of the communication interface (KF3), the address 0 is commonly used. (Warning, when you use the 1770-KF3 device, its setting is valid for all stations of the line).-0
Wait First Timeout
First delay before reading the response after sending a request.ms100
Wait Timeout
Delay between response readings until its finalization.ms100
Max Wait Retry
The number of response readings till its finalization.-40
Max Read Retry
The number of response readings, if the received response is not the response to the expected transaction. All received messages are to confirmed.-10
Retry Count
A retry count of the request in case of a communication failure.-3
Block Read
Enables block data reading. It is executed by non-documented functions - careful proceeding is asdvised.YES/NONO
Max. Block Length
Maximum block length for block reading (in bytes). The value must be an even number within the range of 2 up to 254.-40

I/O tag configuration


Possible I/O tag types: Ai, Ao, Ci, Co, Di, Dout.

I/O tag address is a text address in the SLC-500 format. The address format is:

[$] X [file] : element [.field] [/bit]

in which

$optional character
Xfile type identifier (required - see table No. 4)
filefile number (optional, if not defined, the default file number according to table No. 4 will be used)
elementthe number of an element in the file (required),
.fielda sub-element number (optional, used for Output, Input files only),
/bita bit number (optional, must be within the range of 0..15).

Table 4

XFile TypeDefault file number
OOutput0
IInput1
SStatus2
BBinary3
NInteger7
FFloat8


Output type file

[$]O[n]:e[.s][/b]

"n" the file number, if it is different from the default number 0,
"e" element number in the file,
"s" sub-element number (0..255),
"b" bit number (0..15).

For example:

O:2
$O0:2/0
O:1.0/1

Note: You cannot write into Output files, only read data.


Input type file

[$]I[n]:e[.s][/b]

"n" the file number, if it is different from the default number 1,
"e" element number in the file,
"s" sub-element number (0..255),
"b" bit number (0..15).

For example:

I:1
$I1:2/0
I:2.0/15

Note: You cannot write into Input files, only read data.


Status type file

[$]S[n]:e[/b]

"n"  the file number, if it is different from the default number 2,
"e" element number in the file,
"b" bit number (0..15).

For example:

S:0
$S2:40
S:2/15

Note: You cannot write bit-by-bit into Status type files (output I/O tags with the parameter [/b]).


Binary type file

[$]B[n]:e[/b]

"n"  the file number, if it is different from the default number 3,
"e" element number in the file,
"b" bit number (0..15).

For example:

B:2
$B3:0
B3:2/1


Integer type file

[$]N[n]:e[/b]

"n"  the file number, if it is different from the default number 7,
"e" element number in the file,
"b" bit number (0..15).

For example:

N7:2
$N:0
N27:0/1


Float type file

[$]F[n]:e

"n" file number - if there is used other than the default number of 8,
"e" element number in the file.

For example:

F:0
$F8:0
F29:1

The recommended settings of the 1770-KF3 device


Further recommended parameters for the 1770-KF3 device:

  • Set the Parameter 0 DH-485 Node Address to 0. You can use other address, see „Communication station protocol parameters" - the parameter „IN".
  • Set the parameter 5 DF1 Device Category to DF1 full-duplex.
  • The parameter 6 Error Detection - both BCC and CRC16 can be used, see „Communication station protocol parameters" - the BCC/CRC Checksum parameter.
  • As for the other parameters, the suitable default settings are described in the document „1770-6.5.18, DH-485 Communication Interface User Manual (Cat. No. 1770-KF3)", Allen-Bradley April 1993.

Literature


  • "1770-6.5.18, DH-485 Communication Interface User Manual (Cat. No. 1770-KF3)", Allen-Bradley - April 1993.
  • "1770-6.5.16, DF1 Protocol and Command Set, Reference Manual", Allen-Bradley - October 1996.

Changes and modifications


-

Document revisions


  • Ver. 1.0 - August 22nd, 2000 - document creation.
  • Ver. 1.1 - April 27th, 2009 - update of the document.

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