Mitsubishi Electronics MELSEC-F Manuel D’Utilisation
B-47
5 Buffer Memory (BFM)
5.4 Buffer Memory Details
A
Comm
on I
te
te
ms
B
FX
3U
-4AD
FX
3UC
-4
A
D
C
FX
3U
-4A
D
D
-A
D
P
D
FX
3G
-2A
D
D
-BD
E
FX
3U
-4DA
F
FX
3U
-4D
A
A
-AD
P
P
G
FX
3G
-1D
A
A
-BD
H
FX
3U
-3
A-
ADP
I
FX
3U
-4
A
D
-P
T
-
A
D
P
J
FX
3U
-4A
D
D
-P
TW
-
A
A
D
P
FX
3G
/FX
3U
/FX
3UC
PLC User's Manual - Analog Control Edition
FX
3U
-4AD/FX
3UC
-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 in BFM #200 to #6999.
Channel numbers are respectively assigned to the 4 lower bits of BFM #197. Turn each bit on or off to select
the data history update function.
Channel numbers are respectively assigned to the 4 lower bits of BFM #197. Turn each bit on or off 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 in the buffer memories starting from the smallest BFM numbers.
then overwritten in 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.
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.
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.
Only multiples of 5 are valid.
(If any value from 10 to 14 is set, the sampling cycle will be 10 ms. If any value from 15 to 19 is set, the
sampling cycle will be 15 ms.)
(If any value from 10 to 14 is set, the sampling cycle will be 10 ms. If any value from 15 to 19 is set, the
sampling cycle will be 15 ms.)
2. Caution regarding use of data history function
If the averaging time is set, the data history function cannot be used.
3. Caution regarding EEPROM writing
If data is written to BFM #0, #19, #21, #22, #125 to #129, or #198, the data will also be written to the 4AD
EEPROM.
EEPROM.
→ 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
None of the channels use the digital filter
function.
function.
0
0.5 ms
× number of selected channels (number of
channels using the digital filter function)
1 or more
Set value (ms) in BFM #198
× number of selected
channels (number of channels using the digital filter
function)
function)
One or more channels use the digital filter
function.
function.
9 or less
5 ms
× number of selected channels (number of
channels using the digital filter function)
10 or more
Set value (ms)
*1
in BFM #198 × number of selected
channels (number of channels using the digital filter
function)
function)