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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
Required setting of the 1770-KF3 device

Supported device types and versions


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

Table 1

Device type Meaning Protocol version
Allen-Bradley SLC 5/04 Communication with RS232 via the SLC 5/04 CPU port -
Allen-Bradley 1770-KF3 DH-485 bus concentrator, supports communication with all the devices of the SLC-500 series (description of setting is mentioned at the end of chapter). -

Communication line configuration


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

Line protocol parameters

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

Table 2

Parameter Meaning Unit Default value
BCC/CRC Checksum Type of security by check sum.  CRC
BCC
CRC
Full Debug Activates detailed listings about sending and receiving values. YES/NO NO

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 protocol.

Table 3

Parameter Meaning Unit Default value
Interface Node DH-485 Node Address of the communication interface(KF3), the address in common use is 0. (Warning, when you use the 1770-KF3 device, its setting is valid for all stations of the line). - 0
Wait First Timeout First timeout for reading a response after sending a message. ms 100
Wait Timeout Timeout between response readings till its finalization. ms 100
Max Wait Retry Repetition number of response readings till its finalization. - 40
Max Read Retry Repetition number of response readings, if received response is not the response to expected transaction. All received messages are to be confirmed. - 10
Retry Count Retry count of the request in case of a communication failure. - 3
Block Read Enables block data read. It is executed by non-documented functions - proceed carefully. YES/NO NO
Max. Block Length Maximum block length for block read (in bytes). Value must be a 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 an address in text form in the SLC-500 form. Address format is:

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

in which

$ optional character,
X file type identifier (required - see the table nr. 3),
file file number (optional, if not defined, there will be used the default file number according to the table nr. 3),
element number of element in the file (required),
.field sub-element number (optional, used for Output, Input files only),
/bit bit number (optional, must be within the range of 0..15).

Table 4

X File Type Default file number
O Output 0
I Input 1
S Status 2
B Binary 3
N Integer 7
F Float 8

Output type file

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

"n" file number - if there is used other than the default number of 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" file number - if there is used other than the default number of 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" file number - if there is used other than the default number of 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" file number - if there is used other than the default number of 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" file number - if there is used other than the default number of 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 7,
"e" element number in the file.

For example:

F:0
$F8:0
F29:1

Required setting of the 1770-KF3 device


Further required parameters for 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 - there can be used both BCC and CRC16, see „Communication station protocol parameters" - the parameter „BCC",
  • For the others parameters, there are suitable default settings 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 document.
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