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1.4 Basic Functions
1
(2) Polling Response
As a slave device receives a polling instruction, it transmits an arbitrary size of
response data to the master device.
Response data varies depending on the specifications of the slave device.
The method of reading polling response data from the DN311 by the S controller is
explained in the text dealing with communication with slave devices in Chapter 5.
1.4.2 Bit strobe instruction/response
Bit strobe instruction/response is used to exchange a small size of data between the
master device and slave devices.
With a bit strobe instruction, the master device broadcasts 1-bit output data to all the
slave devices on the basis of its scan list information.
The individual slave devices transmit data (of 0 to 8 bytes) in response to the bit strobe
instruction to the master device. (Bit strobe response). It depends on the specifications
of a slave device how it interprets a bit strobe instruction and what data it transmits as the
bit strobe response.
The slave device must be compatible with the bit strobe instruction/response function in
order for this communication function to be valid.
(1) Bit Strobe Instruction
Data is broadcast to the slave devices on the network that are compatible with the bit
strobe instruction/response function.
The bit strobe instruction contains 64-bit output data, and 1-bit output data is
assigned to each node address on the network (Figure 1-9).
In the example shown in Figure 1-9, the DN311 inputs sensor information using the
bit strobe function and is about to send output control data to the actuator.
The way of transferring bit strobe output data from the S controller to the DN311 is
explained in the text dealing with communication with slave devices in Chapter 5.
Figure 1-9 Example of Bit Strobe Instruction/Response
S controller
Master
DN311
NA=1
Slave 1
proximity
sensor
NA=19
Slave 3
photoelectric
sensor
NA=22
Slave 5
actuator
NA=52
Bit strobe instruction/ Bit strobe response
Slave 2
proximity
sensor
NA=21
Slave 4
photoelectric
sensor
NA=23
0 1 ••• 19 20 21 22 23 24 ••• 51 52 ••• 63
Bit number
Bit strobe instruction data
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