Mitsubishi Electric MELSEC-F FX2N-1HC User Manual page 3

3.3 Buffer memories (BFM)
BFM number
#0
#1
#3,#2
Write #4
#11,#10
#13,#12
#15,#14
#21,#20
Write / Read #23,#22
#25,#24
#26
#27
Read
#29
#30
#5-#9, #16-#19, #28, #31 are reserved.
1) BFM #0 Counter mode (K0 to K11), BFM #1 DOWN/UP command
Count modes
2-phase input
(phase difference pulse)
1-phase 2-input (add/subtract pulse)
1-phase 1-input
a) 32-bit counter modes
A 32-bit binary counter which executes UP/DOWN counting will change
from the lower limit value to the upper limit value or the upper limit value to
the lower limit value when overflow occurs. Both the upper and lower limit
values are fixed values: the upper limit value is +2,147,483,647, and the
lower limit value is -2,147,483,648.
b) 16-bit counter modes
A 16-bit binary counter handles only positive values from 0 to 65,535.
Changes to zero from the upper limit value or to the upper limit value from
zero when overflow occurs; the upper limit value is determined by BFMs #3
and #2.
c) 1-phase 1-input counter (K8 to K11)
• Hardware UP/DOWN (K8, K9)
Phase A
OFF
ON
Phase B
OFF
UP
Current
value
d) 1-phase 2-input counter (K6, K7)
ON
Phase
A input
OFF
ON
Phase
B input
OFF
1 2
e) 2-phase counter (K0 to K5)
•
1 edge-count (K0, K1)
Phase A
+1
Phase B
Phase B input OFF
ON while phase
A input ON Count
up by 1.
•
4 edge-count (K4, K5)
UP COUNT
Phase A input
Phase B input
Counter mode K0 to K11
DOWN/UP command (1-phase 1-input mode)
Ring length Upper/Lower
Command
Preset data Upper/Lower
YH compare value Upper/Lower
YS compare value Upper/Lower
Counter current value Upper/Lower
Maximum count value Upper/Lower
Minimum count value Upper/Lower
Compare results
Terminal status
Error status
Model identification code K4010
32 bits 16 bits
1 edge count
2 edge count
4 edge count
Hardware
UP/DOWN
Software
UP/DOWN
ON
UP/DOWN is
determined by
input phase A
(ON/OFF).
DOWN
Phase A input-1
at OFF ON
Phase B input+1
at OFF ON
3 3 3 2 1 0
+1 -1
Phase B input ON
OFF while phase
A input ON Count
down by 1.
+1
+1 +1
+1
Contents
The counter mode is selected form the
K0 K1
PLC. As shown below, values between K0
K2 K3
and K11 are written to buffer memory BFM
#0 form the PLC. When a value is written to
K4 K5
BFM #0 the contents of BFM #1 to BFM #31
K6 K7
are reset to default values. When setting
this value use a TOP (pulsed) instruction
K8 K9
use M8002 (initial pulse) to drive the TO
instruction.
A continuous command is not allowed.
K10 K11
•
Software UP/DOWN (K10,
BFM#1
Phase B
Current
value
If both phase A and phase B inputs are received
simultaneously, the counter value does not change.
•
2 edge-count (K2, K3)
Phase A
-1
Phase B
DOWN COUNT
Phase A input
Phase B input
Default: K0
Default: K0
Default: K65,536
Default: K0
Default: K0
Default: K32,767
Default: K32,767
Default: K0
Default: K0
Default: K0
0
Lower limit value
-2,147,483,648
0
Ring length
(BFM#3,#2)
K11)
K0 K1
ON
OFF
DOWN
UP
+1 +1
Phase B input OFF Phase B input ON
ON while phase
A input ON Count A input ON Count
up by 1. down by 1.
-1 -1 -1 -1
+2,147,483,647
Upper limit value
UP/DOWN is
determined by
the contents of
BFM #1, (K0/K1).
-1
-1
OFF while phase