Mitsubishi MELSEC-F FX3U Series User Manual

B-47
5 Buffer Memory (BFM)
5.4 Details of Buffer Memories
A
Common Items
B
FX
3UC
-4AD
C
FX
3U
-4AD-ADP
D
FX
3U
-4DA-ADP
E
FX
3U
-4AD-PT
-ADP
F
FX
3U
-4AD-TC
-ADP
G
PID Instruction (FNC 88)
FX 3U /FX 3UC Series PLC User's Manual - Analog Control Edition
FX3UC-4AD (4-channel Analog Input)
5.4.29 BFM #200 to #6999: Data history
Initial value: K0
Numeric data type: Decimal (K)
Use this function to sample the A/D conversion data of each channel and to write the sampled data in the
buffer memories.
4AD can sample up to 1,700 points of A/D conversion data of each channel at the sampling cycle specified in
BFM #198, and can store the sampled data as the history data in the buffer memories as shown in the
following table. Buffer memories are assigned to 4 channels as shown in the following table, and data is
stored in the buffer memories in the order of the smallest BFM number to the largest BFM number.
Use BFM #199 to stop or reset the data history.
1. Caution regarding data history reading
If a large amount of history data is collectively read out to the PLC main unit using FROM instruction, the
watchdog timer error may occur in the PLC main unit. Therefore, when programming, separate the history
data and then read out using FROM instruction. Set WDT (watchdog timer refresh) instruction between the
separated data.
Number of data
sampling times
BFM number
ch1 ch2 ch3 ch4
1st time #200 #1900 #3600 #5300
2nd time #201 #1901 #3601 #4301
3rd time #202 #1902 #3602 #4302
… … … … …
1,700th time #1899 #3599 #5299 #6999

Mitsubishi MELSEC-F FX3U Series Specifications

General

Brand	Mitsubishi
Model	MELSEC-F FX3U Series
Category	Controller
Language	English