Mitsubishi Electric MELSEC FX3U Programming Manual page 126

FX /FX /FX Series Programmable Controllers
3G 3U 3UC
Programming Manual - Basic & Applied Instruction Edition
5. High speed counter device list
Classification
1-phase
1-count input
1-phase
2-count input
2-phase
2-count input
*1. C248 and C253 are usually used as counters having reset input, but can be used as counters C248
(OP) and C253 (OP) not having reset input when used together with special auxiliary relays M8388
and M8392.
*2. C254 is usually used as a counter having reset input and start input, but can be used as a counter
C254 (OP) not having reset input or start input when used together with special auxiliary relays M8388
and M8395.
Notation of high speed counter devices
In some high speed counters in FX
together with special auxiliary relays.
Such high speed counter devices are classified below. Note that description as (OP) is not available in
programming.
Standard Device
Numbers
C248
C253
C254
124
Counter No. Data length
C235
C236
C237
C238
C239 32-bit
C240 bi-directional
C241 counter
C242
C243
C244
C245
C246
*1
C248(OP)
32-bit
C247
bi-directional
C248
counter
C249
C250
C251
*1
C253(OP)
32-bit
*2
C254(OP)
bi-directional
C252
counter
C253
C254
C255
→ For the method to switch the counter function, refer to Subsection 4.8.7.
→ For the method to switch the counter function, refer to Subsection 4.8.6.
PLCs, the input terminal assignment is changed over when used
3G
Switched Device Numbers
C248(OP)
C253(OP)
C254(OP)
4.8 High Speed Counter [C] (FX3G PLCs)
External reset External start
input terminal input terminal
Not provided Not provided
Not provided
Provided
Provided
Provided
Not provided Not provided
Not provided
Provided
Provided
Provided
Not provided Not provided
Not provided
Provided
Provided
Provided
4 Devices in Detail