Link Scan Time - Mitsubishi Electric MELSEC iQ-R Series User Manual

Link scan time

The following is the formula to calculate the link scan time (LS).
Calculation formula
■For the MELSECNET/H mode
• At a communication speed of 10Mbps
LS [ms] = KB + (n  0.45) + {LB + LY + (LW  16)}  8  0.001 + (T  0.001) + (F  4)
• At a communication speed of 25Mbps
LS [ms] = KB + (n  0.40) + {LB + LY + (LW  16)}  8  0.0004 + (T  0.0004) + (F  4)
■For the MELSECNET/H extended mode
• At a communication speed of 10Mbps
LS [ms] = KB + (SP  0.45) + {LB + LY + (LW  16)}  8  0.001 + (T  0.001) + (F  4)
• At a communication speed of 25Mbps
LS [ms] = KB + (SP  0.40) + {LB + LY + (LW  16)}  8  0.0004 + (T  0.0004) + (F  4)
The meanings of the variables and constants in the equation are as follows.
Variable Meaning
n Total number of stations (stations actually connected, not including reserved stations)
SP
n
i=1
n: Total number of stations
The formula to calculate the number of bytes sent is {(LY + LB)  8 + (2  LW)}. The decimal part is rounded up. (If the value is 0, set 1.)
LB Total number of LB points set using LB/LW setting (excluding reserved stations)
LW Total number of LW points set using LB/LW setting (excluding reserved stations)
LY Total number of LY points set using LX/LY setting (1) and LX/LY setting (2) (excluding reserved stations)
T The maximum number of bytes for transient transmissions within one link scan.
F Number of return stations (The maximum value varies depending on the setting.)
*1 Total number of link devices set under "Network Range Assignment" ( Page 55 Network Range Assignment)
*2 This variable means the total number of bytes at each station when the instruction is simultaneously executed from multiple stations.
Constant Total number of stations set under "Network Range Assignment"
N = 1 to 8
KB 4.0
For the link scan time in the MELSECNET/10 mode, refer to the following.
 For QnA/Q4AR MELSECNET/10 Network System Reference Manual
APPX
176
Appendix 6 Processing Time
Number of send bytes in station No. (i)
2000
N = 9 to 16 N = 17 to 24
4.5 4.9
*1
*1
*2
N = 25 to 32 N = 33 to 40
5.3 5.7
*1
N = 41 to 48 N = 49 to 56
6.2 6.6
N = 57 to 64
7.0