■ Timing specifications for instruction and response message
The cautions below are required with regard to the timing to transmit a instruction
message from the master station and a response message from the slave station.
● Response monitor time
The maximum response time from the end of the instruction message transmission
by the master station until when the master station receives a response message
from the slave station is two seconds ((1) in the figure below). So, the response
monitor time should be set to two seconds.
Generally, when a response time-out occurs, the instruction message is resent.
For details, see Chapter 6 “COMMUNICATION PROGRAM FOR MASTER
STATION.”
● Transmission start time
A wait time of 10ms is required before the master station starts to transmit the next
instruction message (to the same slave station or a different slave station) after the
end of receiving response message ((2) in the figure below).
■ RS-485 driver control timing specifications
When the transmission/reception on the RS-485 3-wire system is directly con-
trolled by the master station, care should be paid to the following timing:
(2) End of slave station reception - Driver enable time = 15ms min.
(3) End of slave station transmission - Driver disable time = 10ms max.
(4) End of master station reception - Driver enable time = 10ms min.
Transmission start time of slave station = Max. 2000ms
Transmission start time of master station = Min. 10ms
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