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 type | Meaning | Protocol version |
|---|---|---|
| Allen-Bradley SLC 5/04 | Communication with the SLC 5/04 CPU via RS232 port | - |
| Allen-Bradley 1770-KF3 | DH-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
| Parameter | Meaning | Unit | Default 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/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 the protocol.
Table 3
| Parameter | Meaning | Unit | Default 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. | ms | 100 |
Wait Timeout | Delay between response readings until its finalization. | ms | 100 |
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/NO | NO |
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 |
| X | file type identifier (required - see table No. 4) |
| file | file number (optional, if not defined, the default file number according to table No. 4 will be used) |
| element | the number of an element in the file (required), |
| .field | a sub-element number (optional, used for Output, Input files only), |
| /bit | a 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" 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.
Related pages:
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