Mitsubishi Electric FX3U-232-BD - Calculation Method

E-12
FX Series PLC User's Manual - Data Communication Edition
Inverter Communication
2 Specifications
2.4 Execution Times in Inverter Communication Instructions
2.4.2 Calculation method
Calculate the required time "Tinv" for inverter communication instruction in units of "ms" as follows.
"INT(n)" in the calculation formula indicates an integer obtained by truncating decimal places of "n".
1. Length of 1 character
In inverter communication, the communication setting is as shown in following table.
The length of 1 character is as shown in the following calculation expression.
Length of 1 character = Start bit + Data length + Parity bit + Stop bit
= 10[bit]
2. Execution times in inverter communication instructions
Execution times in inverter communication instructions is as shown in the following calculation expression.
Name Set value bit
Start bit - 1
Data length 7 7
Parity bit Even number 1
Stop bit 1 1
Total 10
Communication
time
Calculation method
T
4
T5 = 1[ms]
T
6[n]
• For Scan time < T
7[n]+T8[n]+T9[n]
• For Scan time  T
7[n]+T8[n]+T9[n]
T
7[n]+T9[n]
T
8[n]
= Data check time in inverters
*4
T3 = 1[ms]
Calculate "T
4", "T5" and "T6 [n]" as shown in the following table.
T
1 = 1[ms]
T
2 = {n(T4+T5)}+T6[n][ms]
T
inv = T1 + T2 + T3
T6[1]+T6[2]+T6[3]+
Sending and
receiving
frequency
= ( INT ( ) + 1)  Scan time
Scan time
15
= ( INT ( ) + 1)  Scan time
Scan time
T
7 [n]+T 8 [n]+T 9 [n]
= ( INT ( ) + 2)  Scan time
Scan time
T
7 [n]+T 8 [n]+T 9 [n]
= { ( )  (  ) }  1000
Communication speed [bps]
1
Number of sending and
receiving characters
*1
Length of
1 character