2. Programming Concepts single frequency mode. The other PLCs support the three modes. 9. C243 and C244 support count-up mode only and occupy the associate input points X1 and X3 as reset (“R”) function. If users do not need to apply reset function, set ON the associated special M relays (M1243 and M1244) to disable the reset function. 10. “Dir” refers to direction control function. OFF indicates counting up; ON indicates counting down. 11. When X1, X3, X4 and X5 is applied for reset function and associated external interrupts are disabled, users can define the reset function as Rising/Falling-edge triggered by special M relays 12.
When X1, X3, X4 and X5 is applied for reset function and external interrupts are applied, the interrupt instructions have the priority in using the input points. In addition, PLC will move the current data in the counters to the associated data registers below then reset the counters. Example: EI M1000 I101 M1000 IRET When C243 is counting and external interrupt is triggerred from X1(I101), counted value in C243 will be move to (D1241, D1240) immediately then C243 is reset. After this interrupt I101 executes. 1-phase 1 input high-speed counter: Example: END LD X20 X20 RST C235 LD X21 OUT M1235 LD X22 DCNT C235 K5 LD C235 OUT Y0 1.
X21 drives M1235 to determine counting direction (Up/Down) of C235. 2. When X20 = ON, RST instsruction executes and the current value in C235 will be cleared. Contact C235 will be OFF 3. When X22 = ON, C235 receives signals from X0 and counter will count up (+1) or count down (-1). 4. When counter C235 reaches K5, contact C235 will be ON. If there is still input signal input for X0, it will keep on counting.
X21 M1235 X22 C235 Y0 2-29 Reset Function X1 X3 X4 X5 R/F M1271 M1273 M1274 M1275 Special D D1241, D1240 D1243, D1242 Counter C243 C246 C248 C252 C244 C250 C254 X1 (I100/I101) X4(I400/I401) X3 (I300/I301) X5(I500/I501) External Interrupt DCNT C243 K100 FEND DMOV D1240 D0 RST C235 DCNT C235 K5