Mitsubishi Electric FX3G SERIES Programming Manual page 106

FX /FX /FX Series Programmable Controllers
3G 3U 3UC
Programming Manual - Basic & Applied Instruction Edition
5. High-speed counter device list
Hardware counter
1-phase
1-count input
Software counter
Hardware counter
1-phase
2-count input
Software counter
Hardware counter
2-phase
2-count input
Software counter
*1. They are handled as software counters depending on the operating condition. When they are handled as
software counters, they have limitations on both maximum response frequency and 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 a special auxiliary relay (M8388, M8390 to M8392).
*4. 2-phase 2-input counter is usually 1 edge count counter, but can be used as a 4 edge count counter by
combining a special auxiliary relay (M8388, M8198 or M8199).
*5. The external reset input is usually reset by turning ON, but can be changed to be reset by turning OFF by
combining special auxiliary relays (M8388 and M8389).
*6. The counter C253 is usually used as a hardware counter, but can be used as the counter C253 (OP) not
equipped with reset input by combining special auxiliary relays (M8388 and M8392).
In this case, C253 (OP) is handled as a software counter.
Notation of high-speed counter devices
For some high-speed counters in FX
auxiliary relays are used.
Such high-speed counter devices are classified below. Note that description as (OP) is not available in programming.
Standard Device Numbers
C244
C245
104
Classification Counter No.
*2
C235
*2
C236
*2
C237
*2
C238
*1
*2
C239
*2
C240
C244(OP)
C245(OP)
C241
C242
C243
*3
C244
*3
C245
*2
C246
*1
*2*3
C248(OP)
C247
*3
C248
C249
C250
*2
C251
*1
*2
C253
C252
C253(OP)
C254
C255
→ For the method to switch the counter function, refer to Subsection 4.7.7.
→ For the method to change the logic of the external reset input, refer to Subsection 4.7.6.
and FX
3U
Switched Device Numbers
C244(OP)
C245(OP)
4.7 High-Speed Counter [C] (FX3U/FX3UC PLC)
Edge count Data length
−
bi-directional
*3
−
*3
−
−
−
bi-directional
−
−
*4
1
*4
4
*4
1
*4
4
*4
1
bi-directional
*4
4
*4
1
*6
*4
4
*4
1
*4
4
→ For the condition handled as software counters,
→ For the total frequency, refer to Subsection 4.7.10.
→ For the wiring, refer to the Hardware Edition of the main unit.
→ For the method to use a 2-phase 2-input 4 edge count counter,
PLCs, the assignment of input terminals will switch when special
3UC
Standard Device Numbers
External reset
input terminal
Not provided
32-bit
counter
*5
Provided
*5
Provided
Not provided
32-bit
*5
Provided
counter
*5
Provided
Not provided
*5
Provided
32-bit
*5
Provided
counter
Not provided
*5
Provided
refer to Subsection 4.7.9.
refer to Subsection 4.7.8.
Switched Device Numbers
C248
C253
4 Devices in Detail
External start
input terminal
Not provided
Not provided
Provided
Not provided
Not provided
Provided
Not provided
Not provided
Provided
C248(OP)
C253(OP)