Omron CQM1H - 08-2005, Operation Manual

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51
For the system shown in the word allocation example on page 49, the time
(Tmax) between the input type Slave input signal turning ON, being read by the
Slave, and then being read by CQM1H/CQM1 from the Master is calculated as
follows (assuming the Slave input ON delay time is 1.5 ms.).
Example calculation of transmission delay time:
The maximum transmission delay time (Tmax) for a system comprising seven
Slaves and one Expansion Master is Tmax = (7+1+2) x 1.2 x 2 + 1.5 = 25.5 ms.
The transmission delay time can be reduced by replacing a large system using
multiple Expansion Masters with multiple Masters configured as separate sys-
tems.
Existing System
Unit 1
Input Slaves 16 x 4-point,
total 64 points
4-point
input
Slave
Output Slaves 8 x 4-point +
4 x 8-point, total 64 points
Transmission delay time (Slave I/O delay time = 1.5 ms)
Tmax = ((28+2+2) x 1.2 x 2 ) + 1.5 = 78.3 ms
Modified System
System 1
Transmission delay time (Slave I/O delay time = 1.5 ms)
Tmax = ((14+0+2) x 1.2 x 2 ) + 1.5 = 39.9 ms
Unit 2
Master
Expansion Master IN Expansion Master OUT
4-point
input
Slave 4-point
input
Slave 4-point
output
Slave 4-point
output
Slave 8-point
output
Slave
Master
4-point
input
Slave 4-point
input
Slave 4-point
input
Slave 4-point
output
Slave 4-point
output
Slave 8-point
output
Slave
Input Slaves 8 x 4-point,
total 32 points Output Slaves 4 x 4-point +
2 x 8-point, total 32 points
System 2
Master
4-point
input
Slave 4-point
input
Slave 4-point
input
Slave 4-point
output
Slave 4-point
output
Slave 8-point
output
Slave
Input Slaves 8 x 4-point,
total 32 points Output Slaves 4 x 4-point +
2 x 8-point, total 32 points
Using one 16-point Unit instead of two 8-point Units reduces the number of
Units, and therefore decreases the transmission delay time.
Reducing Transmission
Delay Time
Transmission Delay Time
Section 4-3