Mitsubishi Electric FX2N-1HC User Manual page 3

3.3 Buffer memories (BFM)
BFM number
#0 Counter mode K0 to K11
#1 DOWN/UP command (1-phase 1-input mode)
#3,#2 Ring length Upper/Lower
Write #4 Command
#11,#10 Preset data Upper/Lower
#13,#12 YH compare value Upper/Lower
#15,#14 YS compare value Upper/Lower
#21,#20 Counter current value Upper/Lower
Write / Read #23,#22 Maximum count value Upper/Lower
#25,#24 Minimum count value Upper/Lower
#26 Compare results
#27 Terminal status
Read
#29 Error status
#30 Model identification code K4010
#5-#9, #16-#19, #28, #31 are reserved.
1) BFM #0 Counter mode (K0 to K11), BFM #1 DOWN/UP command
Count modes
1 edge count
2-phase input
2 edge count
(phase difference pulse)
4 edge count
1-phase 2-input (add/subtract pulse)
Hardware
UP/DOWN
1-phase 1-input
Software
UP/DOWN
a) 32-bit counter modes
A 32-bit binary counter which executes UP/DOWN counting will change
from the lower limit to the upper limit or the upper limit to the lower limit
when overflow occurs. Both the upper and lower limits are fixed values: the
upper limit is +2,147,483,647, and the lower limit 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 or to the upper limit from zero when
overflow occurs; the upper limit 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 DOWN
Current
value
d) 1-phase 2-input counter (K6, K7)
Phase ON
A input
OFF
ON
Phase
B input
OFF
1 2 3 3 3 2 1 0
e) 2-phase counter (K0 to K5)
•
1 edge-count-counter (K0, K1)
Phase A
+1 +1
Phase B
Phase B input OFF
oON while phase
A input ON Count
up by 1.
•
4 edge-count counter (K4, K5)
UP COUNT
Phase A input
+1
+1 +1
Phase B input
32 bits 16 bits
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,
ON
UP/DOWN is
determined by Phase B
input phase A
(ON/OFF).
Current
value
Phase A input-1
If both phase A and phase B inputs are received
at OFFoON
simultaneously, the counter value does not change.
Phase B input+1
at OFFoON
•
2 edge-count counter (K2, K3)
Phase A
-1 -1
Phase B
Phase B input ON
oOFF while phase
A input ON Count
down by 1.
DOWN COUNT
Phase A input
+1
Phase B input
Contents
Default: K0
Default: K0
Default: K65,536
Default: K0
Default: K0
Default: K32,767
Default: K32,767
Default: K0
Default: K0
Default: K0
+2,147,483,647
0
Lower limit
-2,147,483,648
0
Ring length
(BFM#3,#2)
K11)
K0 K1
BFM#1
ON
UP/DOWN is
determined by
the contents of
OFF
BFM #1, (K0/K1).
DOWN
UP
+1 +1
-1
Phase B input OFF Phase B input ON
oON while phase oOFF while phase
A input ON Count A input ON Count
up by 1. down by 1.
-1 -1 -1 -1
Upper limit
-1