Input Assignment For High Speed Counters - Mitsubishi Electric MELSEC FX3U Programming Manual

FX /FX /FX Series Programmable Controllers
3G 3U 3UC
Programming Manual - Basic & Applied Instruction Edition
4.8.2

Input assignment for high speed counters

Inputs X000 to X007 are assigned as shown in the table below according to each high speed counter number.
When a high speed counter is used, the filter constant of a corresponding input number in the main unit
automatically changes (X000, X001, X003 and X004: 10 µs, X002, X005, X006 and X007: 50 µs). Input
terminals not used for high speed counters, however, can be used as general inputs.
→ For the input specifications of the main unit, refer to the Hardware Edition of the main unit.
Counter No.
C235
C236
C237
C238
C239
1-phase
1-count C240
input
C241
C242
C243
C244
C245
C246
C247
1-phase
C248
2-count
C248(OP)
input
C249
C250
C251
C252
C253
2-phase
2-count
C253(OP)
input
C254
C254(OP)
C255
U: Up-counting input
B: B phase input
Restriction to overlap input numbers
• Inputs X000 to X007 are used for high speed counters, input interrupt, pulse catch, SPD/ZRN/DSZR
instructions and general-purpose inputs. When assigning functions, there should be no overlap between
those input terminals.
For example, when C251 is used, X000 and X001 are occupied. As a result, "C235, C236, C241, C244,
C246, C247, C249, C252 and C254", "input interrupt pointers I000 and I101", "pulse catch contacts M8170
and M8171" and "SPD, ZRN and DSZR instructions using X000 and/or X001" cannot be used.
Input terminal assignment
X000 X001 X002 X003
U/D
U/D
U/D
U/D
U/D R
U/D
U/D R
U/D
U D
U D R
U D R
A B
A B R
A B R
D: Down-counting input
R: External reset input
4.8 High Speed Counter [C] (FX3G PLCs)
X004 X005 X006
U/D
U/D
R
U/D R
S
R
U D R
U D
S
U D R
A B R
A B
S
A
A B R
A: A phase input
S: External start input
4 Devices in Detail
X007
S
S
B
S
125
1
2
3
4
5
6
7
8
9
10