Mitsubishi FX3UC SERIES User Manual page 160

FX Series Programmable Controllers
3UC
User's Manual - Hardware Edition
5.5.2 Input allocation of the High-Speed Counter
The high-speed counter numbers are allocated to the input terminals X000 to X007 as shown in the following
table.
When high-speed counters are used, the filter constant of the corresponding input numbers automatically
change (X000 to X005: 5 µs
The input terminals not allocated for high-speed counters can be used as general input terminals.
1. Allocation table
H/W: Hardware counter
A: A-phase input B: B-phase input R: External reset input S: External start input
Type of counter
1-phase 1-count
input
1-phase 2-count
input
2-phase 2-count
*4
input
*1. When the input terminals of the main unit receive pulses having a response frequency of 50k to
100kHz, wire the terminals as stated below.
- The wiring length should be 5m (16'4") or less.
- Connect a bleeder resistance of 1.5kΩ (1 W or more) to the input terminal, so that the load current
of the open collector transistor output on the mating device side to 20mA or more.
*2. When the comparison set/reset instructions (DHSCS, DHSCR, DHSZ and DHSCT) for high-speed
counters are used, the hardware (H/W) counters are switched to software (S/W) counters.
When the input signal logic is inverted by the reset input signal logic switching function (M8388 and
M8389), C253 is switched from a hardware counter to a software counter.
*3. When a special auxiliary relay is driven in a program, the input terminals and their associated
functions are switched.
154
*1
, X006 and X007: 50 µs).
S/W: Software counter
Classifi-
Counter No.
cation
*1 *2
C235 H/W
*1 *2
C236 H/W
*1 *2
C237 H/W
*1 *2
C238 H/W
*1 *2
C239 H/W
*1 *2
C240 H/W
C241 S/W
C242 S/W
C243 S/W
C244 S/W
*3 *2
C244(OP) H/W
C245 S/W
*3 *2
C245(OP) H/W
*1 *2
C246 H/W
C247 S/W
C248 S/W
*1*3 *2
C248(OP) H/W
C249 S/W
C250 S/W
*1 *2
C251 H/W
C252 S/W
*1 *2
C253 H/W
*3
S/W
C253(OP)
C254 S/W
C255 S/W
→ For the conditions under which it is handled as a software counter,
→ For the procedures on switching to hardware counters, refer to Subsection 5.5.6.
5 Input Specifications and External wiring
5.5 High-speed Counters (C235 to C255)
U: Up-count input
Input allocation
X000 X001 X002 X003
U/D
U/D
U/D
U/D
U/D R
U/D R
U/D R
U/D R
U D
U D R
U
U
U D R
U
A B
A B R
A
A
A B R
A
→ For the wiring, refer to Section 7.2.
D: Down-count input
X004 X005 X006 X007
U/D
U/D
U/D R
S
U/D
S
U/D
D R
D
S
D R S
B R
B
S
B R S
refer to Subsection 5.5.8.