Communication possibilities with
Allen Bradley PLC devices by the
Rockwell Automation company:
The DF1 protocol
It goes about the communication protocol designated for serial link (
RS232/RS422).
The protocol allows the communication either
Full-duplex (point-to-point type of connection,
RS232) or
Half-duplex (1
Master x n
Slave) with addressing the PLC stations.
This protocol is supported by PLC devices that work with data areas (
DataFile), for example:
SLC500,
MicroLogix, etc.
For this communication in the PROMOTIC system can be used:
The Ethernet/IP protocol
It is built on the
NetLinx architecture that is implemented even in
DeviceNet and
ControlNet networks.
Ethernet/IP is administered by the
ODVA independent organization that even takes charge of
DeviceNet.
This protocol is supported by PLC devices that work with data objects (contrary to the data areas for the
DF1 protocol).
For example the following PLC devices:
Micro820,
ControlLogix,
CompactLogix,
SoftLogix,
DriveLogix,
GuardLogix,
Micro850,
Micro870 etc.
For this communication in the PROMOTIC system can be used:
Another way of the communication by the
Ethernet/IP protocol is based on using the software
OPC server RSLinks OEM AB.
The Modbus protocol
Modbus is standard, very commonly used protocol for Ethernet-client and for serial link (PLC device is
Slave).
- The
Modbus RTU protocol is supported for example by:
Micro820,
MicroLogix 1200/1100/1500.
- The
Modbus TCP/IP protocol is supported for example by:
Micro820,
Micrologix1400.
For this communication in the PROMOTIC system can be used:
The ASCII protocol
It goes about the configurable char communication protocol designated for serial link (
RS232/RS422).
This protocol is supported by some PLC devices, for example:
Micro820,
CompactLogix (on the second serial link port),
MicroLogix 1100/1200/1500, etc.
For this communication in the PROMOTIC system can be used:
The DH+ protocol
It supports 64 nodes at the most, 230 kB/s (
SLC 501 to 3 can't it).
It is the proprietary
Allen-Bradley protocol.
For communication of the PROMOTIC application two methods can be used:
1)
HW communication card: It is
HW card PkTX for PCI into the computer.
For communication of the PROMOTIC application with this card,
OPC server RSLinks OEM AB can be used - see
Communication by OPC interface.
2)
External converter DF1/DH+: For communication of the PROMOTIC application with this converter, the
PmABradleyDF1 communication driver can be used.
The DH485 protocol
It goes about the communication protocol designated for serial link.
It supports max. 32 nodes, 19 kB/s (
multi-master = communication each-to-each).
It is the proprietary
Allen-Bradley protocol.
For communication of the PROMOTIC application two methods can be used:
1) HW communication card: For description see DH+ protocol.
2)
External converter DF1/DH485: (e.g.
1747-UIC or older
1770-KF3). For communication of the PROMOTIC application with this converter, the
PmABradleyDF1 communication driver can be used.
Remarks to some PLCs
- The SLC500, MicroLogix 1000, 1200, 1500 PLC devices, PLC5 and ControlLogix L6x are now considered obsolete (year 2026).
- The
MicroLogix 1400 PLC device is probably also obsolete (year 2026). It is the last manufactured PLC device with the
DF1 protocol (
CIP/DF1).
- The PLC devices ControlLogix and CompactLogix for compatibility with older PLCs can emulate data files as they were in older PLC devices - e.g. creates an array containing n values of type of data types INT and assigns it the file index 10 and then can be read via the DF1 protocol (CIP/DF1) as N10:0÷n.
This is how you can convert SLC500 to CompactLogix without making any changes to the PROMOTIC application.
- The
MicroLogic1100 PLC device communicates with these protocols:
