Timers. Time Value: Bits 0 through 9 of the timer word contain the time value in binary code.

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Caitlin Shelton
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1 Timers Memory Area: Timers have an area reserved for them in the memory of your CPU. This memory area reserves one 16-bit word for each timer address. When you program in FBD, 256 timers are supported. (T0-T255) Updating of timer words by the clock timing. In the RUN mode, this CPU function decrements a given time value by one unit at the interval specified by the time base until the time value is zero. S: Start input BI: Time remaining (value in integer format) TV: Preset time value (range ) BCD: Time remaining (value in BCD format) R: Reset input Q: Status of the timer Time Value: Bits 0 through 9 of the timer word contain the time value in binary code. S5T#aH_bM_cS_dMS - Where H = hours, M = minutes, S = seconds, and MS = milliseconds; a, b, c, d are defined by the user. S5TIME#4S = 4 seconds s5t#2h_15m = 2 hours and 15 minutes S5T#1H_12M_18S = 1 hour, 12 minutes, and 18 seconds The maximum time value that you can enter is 9,990 seconds, or 2H_46M_30S. Time Base: Bits 12 and 13 of the timer word contain the time base in binary code. Bit Configuration in the Timer Cell: When a timer is started, the contents of the timer cell are used as the time value. Bits 0 through 11 of the timer cell contain the time value in binary coded decimal format (BCD format: each group of four bits contains the binary code for one decimal value). Bits 12 and 13 contain the time base in binary code. The following Figure shows the contents of the timer cell loaded with timer value 127 with a time base of 1 second.

2 Reading the Time and the Time Base: Each timer box provides two outputs, BI and BCD, for which you can specify a word location. The BI output provides the time value in binary format, the time base is not displayed. The BCD output provides the time base and the time value in binary coded decimal (BCD) format. Choosing the right Timer:

3 S_PULSE : Pulse Timer S_PEXT : Extended Pulse Timer S_ODT : On-Delay Timer S_ODTS : Retentive On- Delay Timer

4 S_OFFDT : Off-Delay Timer SP : Start Pulse Timer SE : Start Extended Pulse Timer SD : Start On-Delay Timer SS : Start Retentive On- Delay Timer SF Start Off-Delay Timer

5 Counters Area in Memory: Counters have an area reserved for them in the memory of your CPU. This memory area reserves one 16-bit word for each counter address. When you program in FBD, 256 counters are supported. (C0-C255) CU: Up Counter CD: Down Counter CV: Current count value (HEX number) PV: Count value in the range (0-999) CV_BCD: Current count value (BCD) R: Reset input S: presetting the counter Q: Status of the counter Count Value: Bits 0 through 9 of the counter word contain the count value in binary code. The count value is moved to the counter word when a counter is set. The range of the count value is 0 to 999. Bit Configuration in the Counter: You provide a counter with a preset value by entering a number from 0 to 999, for example 127, in the following format: C#127. The C# stands for binary coded decimal format (BCD format: each set of four bits contains the binary code for one decimal value). Bits 0 through 11 of the counter contain the count value in binary coded decimal format.

6 Use Set for Count Down Use Reset for Count Up S_CUD : Assign Parameters and Count Up/Down S_CU : Assign Parameters and Count Up S_CD : Assign Parameters and Count Down SC : Set Counter Value CU : Up Counter CD : Down Counter Comparison IN1 and IN2 are compared according to the type of comparison you choose: == IN1 is equal to IN2 <> IN1 is not equal to IN2 > IN1 is greater than IN2 < IN1 is less than IN2 >= IN1 is greater than or equal to IN2 <= IN1 is less than or equal to IN2 If the comparison is true, the RLO of the function is "1". Otherwise, it is 0. CMP? I : Compare Integer CMP? D : Compare Double Integer CMP? R : Compare Real

7 CMP? I : Compare Integer (16-Bit Floating Point Numbers) CMP? D : Compare Double Integer (32-Bit Floating Point Numbers) CMP? R : Compare Real (32-Bit Floating Point Numbers) Examples for Timers 1.Y Δ Control

8 2.Sequential Control 3.Extend Beyond the Maximum Time Limit: Since the maximum time value that you can enter is 9,990 seconds, or 2H_46M_30S, how can you use timers for 4 hours? 4. Traffic Lights (See the next page.) Examples for Counters 1.Extend Beyond the Maximum Counter Limit: Since the maximum counter value that you can enter is 999, how can you use counters for 15,000? 2. Car Parking (See the next page.)

9 TRAFFIC LIGHTS MODES: 1. Normal 2. Timed ( Busy, Normal, Night) 3. Emergency 1) Flashing Yellow Lights 2) Flashing Red Lights

10 AUTOMATIC CAR PARK

SIMATIC. Function Block Diagram (FBD) for S7-300 and S7-400 Programming. Preface. Bit Logic Instructions. Comparsion Instructions

SIMATIC. Function Block Diagram (FBD) for S7-300 and S7-400 Programming. Preface. Bit Logic Instructions. Comparsion Instructions s SIMATIC Function Block Diagram (FBD) for S7-300 and S7-400 Programming Reference Manual Preface Bit Logic Instructions 1 Comparsion Instructions 2 Conversion Instructions 3 Counter Instructions 4 Data