Bfm#200 To #6999: Data History - Mitsubishi Electric FX3G User Manual

FX /FX /FX /FX /FX
3S 3G 3GC 3U
FX -4AD/FX -4AD (4-channel Analog Input)
3U 3UC

5.4.29 BFM#200 to #6999: Data history

Use this function to sample the A/D conversion data of each channel and to write the sampled data to the
buffer memories.
The 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 history data in the buffer memories as shown in the
following table. Buffer memories are assigned to the 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.
Number of data
samples
1st
2nd
3rd
1,700th
1. Caution regarding data history reading
If a large amount of history data is collectively read out to the PLC main unit using the FROM instruction, the
watchdog timer error may occur in the PLC main unit. Therefore, when programming, separate the history
data and then read it out using the FROM instruction. Set WDT (watchdog timer refresh) instruction between
the separated data.
B-48
PLC User's Manual - Analog Control Edition
3UC
ch1
#200
#201
#202
#1899
BFM number
ch2 ch3
#1900 #3600
#1901 #3601
#1902 #3602
#3599 #5299
5 Buffer Memory (BFM)
5.4 Buffer Memory Details
Initial value: K0
Numeric data type: Decimal (K)
ch4
#5300
#5301
#5302
#6999