Publication 1766-RM001A-EN-P - October 2008
604 Protocol Configuration
DF1 Radio Modem
Protocol
This driver implements a protocol, optimized for use with radio modem
networks, that is a hybrid between DF1 Full-Duplex and DF1 Half-Duplex
protocols and is not compatible with either protocol.
The primary advantage of using DF1 Radio Modem protocol for radio
modem networks is in transmission efficiency. Each read/write transaction
(command and reply) requires only one transmission by the initiator (to
send the command) and one transmission by the responder (to return the
reply). This minimizes the number of times the radios need to “key-up” to
transmit, which maximizes radio life and minimizes radio power
consumption. It also maximizes communication throughput. In contrast,
DF1 Half-Duplex protocol requires five transmissions for the DF1 Master
to complete a read/write transaction with a DF1 Slave – three by the
master and two by the slave.
RTS Send Delay
(x20 ms)
0…65535 (can be set in 20 ms increments) – only with control line set to “Half Duplex Modem
(RTS/CTS Handshaking)”
Specifies the time delay between setting RTS until checking for the CTS response. For use with
modems that are not ready to respond with CTS immediately upon receipt of RTS.
0
Message Retries 0…255
Specifies the number of times the master device attempts to re-send a message packet when it
does not receive an ACK from the slave device. For use in noisy environments where
acknowledgements may become corrupted in transmission.
3
Pre Transmit Delay
(x1 ms)
0…65535 (can be set in 1 ms increments)
When the Control Line is set to “No Handshaking”, this is the delay time before transmission.
Required for 1761-NET-AIC physical Half-Duplex networks. The 1761-NET-AIC needs 2 ms of delay
time to change from transmit to receive mode.
When the Control Line is set to “Half-Duplex Modem (RTS/CTS Handshaking)”, this is the
minimum time delay between receiving the last character of a packet and the next RTS assertion.
0
DF1 Half-Duplex Slave Configuration Parameters
Parameter Options Programming
Software
Default
IMPORTANT
The DF1 Radio Modem driver should only be used among devices that
support and are configured for the DF1 Radio Modem protocol. DF1 Radio
Modem protocol is currently supported by SLC 5/03, 5/04 and 5/05
controllers; MicroLogix 1400, 1200 and 1500 controllers; and Logix
controllers at Version 16.1 firmware or higher.
efesotomasyon.com - Allen Bradley,Rockwell,plc,servo,drive
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