How devicenet bricks act – GE Industrial Solutions OKCV3000CN DeviceNet User Manual

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5.3. HOW DEVICENET BRICKS ACT

To use the DeviceNet Bricks you must remember the following:

there are 3 Bricks:

CFIX is the Brick on the master card

RFIX and WFIX are Bricks on the slave card

the slave reads/writes in the FWA;

the master reads/writes its own IVAR and decides where to write/read in the slave-

the master acts as follows

during IDLE-to-READY, CFIX Bricks is analyzed and some values are fixed

during IDLE-to-READY, DeviceNet system software starts to establish connections with the slave mapped

in parameters “SlaveMapLow” and “SlaveMapHig”

in READY state no Bricks program is executed

in READY state DeviceNet system software transmits/receives some meaningless words of FWA to main-
tain the I/O connections opened (only with connections already established)

during READY-to-RUN DeviceNet system software deletes every meaningless transmission still pending

in RUN state the Bricks program is executed. When a CFIX is executed, transmission over the network is

done (or scheduled if the transmitter is busy), only if the connection is established

during RUN-to-READY the pending transmissions are deleted

in READY state DeviceNet system software transmits/receives some meaningless words of FWA to main-
tain the 110 connections opened

during READY-to-IDLE DeviceNet system software deletes all connections still open;

in IDLE no master communication occurs

the slave acts as follows

regardless of the DGFC state (IDLE/READY/RUN) DeviceNet system software answers to master, if con-
nection is established

AUENT,oN:

DGFC can be master and slave simultaneously.

k2Z

HOW TO EXCHANGE I/O DATA