Mitsubishi Electric MELSEC-Q Structured Programming Manual page 66

FXCPU Structured Programming Manual
[Device & Common]
5. High speed counter list
1) In FX /FX
3U
Classification
Hardware
counters
Software
counters
Hardware
counters
Software
counters
Hardware
counters
Software
counters
*1. They are handled as software counters depending on the operating condition. When they are handled
as software counters, they get restrictions of both the maximum response frequency and the total
frequency.
*2. Cautions on wiring should be considered for these high speed counters.
*3. C244, C245 and C248 are usually used as software counters, but can be used as hardware counters
C244 (OP), C245 (OP) and C248 (OP) by combining special auxiliary relays (M8388 and one among
M8390 to M8392).
*4. 2-phase 2-input counters usually execute 1-edge counting, but can be used for 4-edge counting by
combining special auxiliary relays (M8388 and one between M8198 and M8199).
→ For the method to use a 2-phase 2-input counter for 4-edge counting, refer to Subsection 2.7.8.
*5. The external reset input usually causes reset at turning ON, but can cause reset at turning OFF by
combining special auxiliary relays (M8388 and M8389).
*6. C253 is usually used as a hardware counter, but can be used as a counter C253 (OP) not having
reset input by combining special auxiliary relays (M8388 and M8392).
In this case, C253 (OP) is handled as a software counter.
64
PLCs
3UC
1-edge counting/
Counter No.
4-edge counting
*2
C235
*2
C236
*2
C237
*2
C238
*2
*1
C239
*2
C240
*3
C244(OP)
*3
C245(OP)
C241
C242
C243
*3
C244
*3
C245
*2
C246
*1
*2*3
C248(OP)
C247
*3
C248
C249
C250
1-edge counting
*2
C251
4-edge counting
*1
1-edge counting
*2
C253
4-edge counting
1-edge counting
C252
4-edge counting
1-edge counting
*6
C253(OP)
4-edge counting
1-edge counting
C254
C255
4-edge counting
→ For the condition handled as software counters, refer to Subsection 2.7.9.
→ For the wiring, refer to the manual (Hardware Edition) of the PLC main unit.
→ For the method to switch the counter function, refer to Subsection 2.7.7.
→ For the method to change the logic for external reset input, refer to Subsection 2.7.6.
Data length
-
32-bit
bidirectional
-
counter
-
-
-
32-bit
- bidirectional
counter
-
*4
*4
*4
*4
32-bit
*4
bidirectional
*4
counter
*4
*4
*4
*4
→ For the total frequency, refer to Subsection 2.7.10.
2 Devices in Detail
2.7 High Speed Counter [C]
External reset input External start input
terminal
Not provided Not provided
*5
Not provided
Provided
*5
Provided
Not provided Not provided
*5
Not provided
Provided
*5
Provided
Not provided
Not provided
*5
Provided
*5
Provided
Not provided
Not provided
*5
Provided
terminal
Provided
Provided
Provided