7 Application Instructions API 50-99 5. When parameter setting exceeds its range, the upper bound and lower bound will become the setting value. However, if the motion direction (DIR) exceeds the range, it will be set to 0. 6. PID instruction can be used in interruption subroutines, step points and CJ instruction. 7. The maximum error of sampling time T S = - (1 scan time + 1ms) ~ + (1 scan time). When the error affects the output, please fix the scan time or execute PID instruction in the interruption subroutine of the timer. 8. PV of PID instruction has to be stable before the execution of PID instruction.
If you are to extract the input value of DVP04AD/04DA/06XA/04PT/04TC for PID operation, please be aware of the A/D conversion time of these modules. 9. For the 32-bit instruction, If S 3 designates the parameter setting area of PID instruction as D100 ~ D120, S 3 occupies 21 registers. Before the execution of PID instruction, you have to use MOV instrction first to send the setting value to the register area for setup. If the designated registers are latched one, use MOVP instruction to send all the setting value at a time. 10. Settings of S 3 in the 32-bit instruction DVP-PLC APPLICATION MANUAL 7-135 Device No. Function Setup Range Explanation S +7:
3 Lower bound of output value (MV) -32,768 ~ 32,767 Ex: if S +7 is set as -1,000, the output will be 3 -1,000 when MV is smaller than -1,000. S +8: 3 Upper bound of integral value -32,768~32,767 Ex: if S +8 is set as 1,000, the output will be 3 1,000 when the integral value is bigger than 1,000 and the integration will stop. S +8 has to 3 be bigger or equal S +9; otherwier the upper 3 bound and lower bound will switch. S +9: 3 Lower bound of integral value -32,768 ~ 32,767 Ex: if S +9 is set as -1,000, the output will be 3 -1,000 when the integral value is smaller than -1,000 and the integration will stop. If S +8 and 3 S +9 are set to 0, there will be no upper limit for 3 integration.
S +10,11: 3 Accumulated integral value 32-bit floating point The accumulated integral value is only for reference. You can still clear or modify it (in 32-bit floating point) according to your need. S +12: 3 The previous PV -32,768~32,767 The previous PV is only for reference. You can still modify it according to your need. S +13: 3 ~ S +19: 3 For system use only. Device No. Function Setup range Explanation S : 3 Sampling time (T ) S (unit: 10ms) 1 ~ 2,000 (unit: 10ms) If T is less than 1 program scan time, PID S instruction will be executed for 1 program scan time. If T = 0, PID instruction will not be S enabled. The minimum T has to be longer S than the program scan time.