Specifications

Allen-Bradley DF1 Driver Help
l If the destination device is not on a DH+ or DH-485 network, the device being communicated with is a
Micrologix, SLC500, or PLC-5 PLC. The station number for this configuration can be set to an arbitrary
unique address.
Standard Serial Configuration
Station Number = Arbitrary unique address on the network for the local PC. The range for DH-485 is 1 to 63.
Otherwise, the range is 0 to 255.
DH+/DH-485 Converter Configuration
Station Number = Converter's node address (e.g. KF2/KF3 node address).
Link Protocol
The Allen-Bradley DF1 Driver implements the following link protocols:
Standard Serial Configuration
Full-Duplex (a.k.a Allen-Bradley DF1 )
Half-Duplex Master (a.k.a Polled-Mode)
KF2/KF3 Half-Duplex Master
Radio Modem
DH+/DH-485 Converter Configuration
Full-Duplex (a.k.a Allen-Bradley DF1 )
KF2/KF3 Half-Duplex Master
Slave Re-Poll Delay (ms)
For more information, refer to Slave Re-Poll Delay.
Only accept responses for Station Num
For more information, refer to Full-Duplex.
Full Duplex
Full-duplex protocol is used over a point-to-point link, allowing for high performance two-way communications
between peers.
Only accept responses for Station Num:
When checked, this parameter limits the acceptance of responses to those that are destined for the station as
indicated by the Station Num field.
Half Duplex Master
Half-Duplex Protocol is a multi-drop protocol with one master and one or more slaves. Generally, Half-Duplex
provides lower data throughput than Full Duplex, but it adds the flexibility of being able to communicate with
multiple devices from a single COM port. Half-Duplex is a master/slave protocol. In Half-Duplex Master mode, the
driver is the master and all devices on the network are slaves. It is necessary that all the devices on the network
be configured as Half-Duplex Slave since only one master is allowed on the network. For more information on
configuring the Micrologix/SLC500/PLC5 device using RSLogix, refer to the Rockwell documentation.
Note: If the destination device is on a DH-485 or DH+ network, communication must go through a KF2/KF3
module respectively. If the KF2/KF3 module is configured as a Half-Duplex Slave, the KF2/KF3 Half-Duplex
Master Link Protocol must be chosen.
Master Responsibilities and Update Rates
The driver (master) is responsible for polling the slaves for data. In general, slaves would be polled in a round-
robin manner. Due to the nature of OPC, how often a slave gets polled depends on the slave tags' update rate. In
this manner, slaves are only polled when a Read/Write operation is requested from them. This reduces the traffic
on the network and prevents unnecessary requests from taking place. In essence, the design of the client project
(specifically update rates assigned) determines the traffic on the network. The faster the update rate, the more
often a slave will be polled.
Messages, Sink and Source
There are three messages exchanged between master and slave in a Read/Write operation. The first is the master
message requesting the slave to perform a Read/Write operation. The slave does not respond immediately with
data as in full-duplex mode. The second message is a poll message from the master to the slave requesting the
data gathered from the last master message operation. The third is the slave response with the data requested in
www. kepware.com
7