B-45
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)
5.4.26 BFM #197: Selection of cyclic data update function (function for data history)
Initial value: H0000
Numeric data type: Hexadecimal (H)
Use this function to update the data history is BFM #200 to #6999.
Channel numbers are respectively assigned to 4 lower bits of BFM #197. Turn on or off each bit to select the
data history update function.
ON: If a bit is turned on, the corresponding data will be stored in the buffer memories in the order of the
smallest BFM number to the largest BFM number, but when 1,700 points of data are stored, data will be
then overwritten on the buffer memories starting from the smallest BFM numbers.
OFF: If a bit is turned off, the corresponding data will be stored in the buffer memories in the order of the
smallest BFM number to the largest BFM number, but when 1,700 points of data are stored, data
storage will stop.
5.4.27 BFM #198: Data history sampling time setting
Setting range: 0 to 30000
Initial value (at delivery) : K15000
Numeric data type: Decimal (K)
Use this function to set the data history sampling time.
If one of the channels uses the digital filter function, set a multiple of 5.
1. Sampling cycle
As shown in the following table, the sampling cycle depends on whether the digital filter function is used.
*1. Multiples of 5 only are valid.
(If any value of 10 to 14 is set, the sampling cycle will be 10 ms. If any value of 15 to 19 is set, the
sampling cycle will be 15 ms.)
2. Caution regarding use of data history function
If the number of averaging time is set, the data history function cannot be used.
3. Caution regarding EEPROM writing
If data is set in BFM #0, #19, #21, #22, #125 to #129, or #198, the data will be written in the EEPROM of 4AD.
→ For a detailed description of cautions regarding EEPROM writing, refer to Subsection 5.4.1.
1. Channel number assignment to each bit of BFM #197
Bit No. Description History data stored in
b0 Selection of channel-1 data update function BFM #200 to #1899, 1,700 points
b1 Selection of channel-2 data update function BFM #1900 to #3599, 1,700 points
b2 Selection of channel-3 data update function BFM #3600 to #5299, 1,700 points
b3 Selection of channel-4 data update function BFM #5300 to #6999, 1,700 points
b4 to b15 Not used. -
Whether digital filter function is used
Value set in
BFM #198
Sampling cycle
Non of the channels use the digital filter
function.
0
0.5 ms × number of selected channels (for use of digital
filter function)
1 or more
Set value (ms) in BFM #198 × number of selected
channels (for use of digital filter function)
One or more channels use the digital filter
function.
9 or less
5 ms × number of selected channels (for use of digital
filter function)
10 or more
Set value (ms)
*1
in BFM #198 × number of selected
channels (for use of digital filter function)
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