15. Handy Instruction Design Examples M1 Store the operation result of FTC instruction in D22 M1013 Y0 outputs pulses (width determined by D22) Sample present temp. every 1 sec and store it in D11 Program Description: z FTC instruction is a handy instruction exclusively designed for temperature control. Unlike the large amount of parameters required by PID instruction, users only need to set a few parameters. z Format of FTC instruction: S 1 → Set value (SV) (Range:1~5000, shown as 0.1 ° ~500 ° ) S 2 → Present value (PV) (Range:1~5000, shown as 0.1 ° ~500 ° ) S 3 → Parameter (Users need to set parameters S 3 and S 3 ＋ 1) D → Output value (MV) (Range:
0 ~ S 3 *100) z Setting of S 3 and S 3 ＋ 1: z In practical application, users usually need to adjust S 3 and S 3 ＋ 1 several times to get the best control results. The basic rules are as follows: 1. Sampling time should be set to 2 times more than the sampling time of the temperature sensor, generally between 2s ~6s. 2. The cycle time of GPWM instruction is the same with the sampling time of FTC instruction, but the unit for GPWM cycle time is 1ms. 3. Properly decrease SV of the sampling time if the control duration is too long. 4. Properly increase SV of the sampling time if the fluctuations occur frequently. 5.
“General heating environment” (b3 = 1) is the default setting for the heating DVP-PLC Application Examples 15-19 FTC D10 D11 D12 D22 GPWM D22 D30 Y0 FROM K0 K6 D11 K1 FTC S 1 S 2 S 3 D Device Function Range S 3 Sampling time (Ts) 1~200 (unit: 100ms) S ＋1 3 b0: temperature unit b1: filter function b2: heating environment b3~b15: reserved b0 = 0 means ℃; b0 = 1 means ℉ b1 = 0 means without filter function; b1 = 1 means with filter function b2 = 1 Slow heating environment b3 = 1 General heating environment b4 = 1 Fast heating environment b5 = 1 High-speed heating environment