55
Transmission Delay Time Section 4-3
Refer to the CQM1H Operation Manual (W363) or the CQM1 Operation Man-
ual (W226) for details about the CQM1H/CQM1 and unit response times.
Refer to I/O Terminal Series Catalog (X044) for details about the Slave I/O
ON/OFF delay times.
For the system shown in the word allocation example on page 53, 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 calcu-
lated 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.
Reducing Transmission
Delay Time
The transmission delay time can be reduced by replacing a large system
using multiple Expansion Masters with multiple Masters configured as sepa-
rate systems.
Using one 16-point Unit instead of two 8-point Units reduces the number of
Units, and therefore decreases the transmission delay time.
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
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