Mitsubishi FX3UC Series - Page 160

154
FX3UC Series Programmable Controllers
User’s Manual - Hardware Edition
5 Input Specifications and External wiring
5.5 High-speed Counters (C235 to C255)
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
*1
, X006 and X007: 50 µs).
The input terminals not allocated for high-speed counters can be used as general input terminals.
1. Allocation table
H/W: Hardware counter S/W: Software counter U: Up-count input D: Down-count input
A: A-phase input B: B-phase input R: External reset input S: External start 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.
→ For the wiring, refer to Section 7.2.
*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.
→ For the conditions under which it is handled as a software counter,
refer to Subsection 5.5.8.
*3. When a special auxiliary relay is driven in a program, the input terminals and their associated
functions are switched.
→ For the procedures on switching to hardware counters, refer to Subsection 5.5.6.
Type of counter Counter No.
Classifi-
cation
Input allocation
X000 X001 X002 X003 X004 X005 X006 X007
1-phase 1-count
input
C235
*1
H/W
*2
U/D
C236
*1
H/W
*2
U/D
C237
*1
H/W
*2
U/D
C238
*1
H/W
*2
U/D
C239
*1
H/W
*2
U/D
C240
*1
H/W
*2
U/D
C241 S/W
U/D R
C242 S/W
U/D R
C243 S/W
U/D R
C244 S/W
U/D R S
C244(OP)
*3
H/W
*2
U/D
C245 S/W
U/D R S
C245(OP)
*3
H/W
*2
U/D
1-phase 2-count
input
C246
*1
H/W
*2
U D
C247 S/W
U D R
C248 S/W
U D R
C248(OP)
*1*3
H/W
*2
U D
C249 S/W
U D R S
C250 S/W
U D R S
2-phase 2-count
input
*4
C251
*1
H/W
*2
A B
C252 S/W
A B R
C253
*1
H/W
*2
A B R
C253(OP)
*3
S/W A B
C254 S/W
A B R S
C255 S/W
A B R S