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3 SPECIFICATIONS AND FUNCTIONS
(2) When master module is QJ61BT11N
(a)
Calculation expression
Details
Master module
(write (RIWT command))
Master module
(read (RIRD command))
OT : QCPU dedicated command processing time
QnCPU
QnHCPU
SM : Scan time of master module sequence program
LS : Link scan time (refer to the Master Module User's Manual)
BC
156kbps
6
(b)
Calculation example
The following example calculates the transmission delay time taken when
Md.30
"
Machine feed value" (2 words) is read from the D75P2 when the
Q06HCPU is used.
When SM is 20ms, transmission speed is 10Mbps, and only one D75P2 is
connected
LS : 1.8ms (for the calculation expression, refer to "(2) Calculation
example in Cyclic transmission")
Transmission delay time = OT + LS {BC + (2 + 16)/16 1.067}
However, when data is read from the buffer memory whose update timing is at
56.8ms intervals
shown below depending on the read timing.
D75P2 update timing
Md. 30 Machine feed value
Calculation expression (Unit: ms)
D75P2
OT + LS {BC + (number of write points
D75P2
OT + LS {BC + (number of read points
:
1[ms]
: 0.5[ms]
625kbps
2.5Mbps
7
= 0.5 + 1.8 {12 + (2 + 16)/16 1.067}
= 0.5 + 1.8
25.9[ms]
*1
, data after a maximum of 25.9 + 56.8 = 82.7ms is read as
*1
56.8ms
56.8ms
1)
25.9+1) (ms)
Read
execution
3 - 34
*1
*1
*1: Set in word unit
*2: Rounded up to the one place
5Mbps
9
11
14.134
Md.37
update timing is at 910ms intervals.
56.8ms
Read
complete
MELSEC-A
*2
+ 16)/72
1.13}
*2
+ 16)/16
1.067}
10Mbps
12
56.8ms
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