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Special Timers of mitsubishi PLC comes with both functionality of TT and Done bit of TOFF and TON timers. Special timer Here STMR is the is the special timer function, To is the TON timer, K100 is the preset value(you can give K10,K200, etc depending upon of the preset you require), and M0 is the result of the timer. here i have used memory address M0 to store result of timer, and in Special timer the next three consecutive memory addresses are automatically assigned to store TT and Done bits of timers. Here M0 is used to store the Done bit of TOFF timer,M1 for the TT bit of TOFF timer, M2 for TT bit of the TON timer, and the last M3 bit is used to store both Done bits of TON ans TOFF timers(first it works as a done bit of the TON timer and then it works as a done bit of the TOFF timer). Timing diagram for special timer. Above fig. shows timing diagram of the special timer with timing diagram with preset value of 5 sec. DN bit TOFF :- This bit is used, when

Retentive timers are used to retain and count only ON time of Input, and once the total ON time of input goes beyond pre-set value of Timer, Timers Done bit goes ON. Retentive timer stops counting time when input gets OFF but it retains the previous counted time duration of input. Suppose you have a Input which gets ON and OFF very frequently and you want to turn ON a Output if the total ON time duration of Input is 10 Sec, so in that case you can use the retentive Timer. retentive timer. Above fig. shows retentive timer instruction and its timing diagram in Mitsubishi PLC. Here the Tiemr T250 is a retentive timer who's time base is 100 m sec so to set the preset value of timer for 10 sec we have entered 100 as a preset value. for more details of conversion please refer the table in my Timer instruction post .  From the above fig. its clear that when we press the input of address X000, then retentive timer starts counting ON time. When we release the input X000

In mitsubishi PLC Gx-Developer programming software we have total 512 timers From T0 - T511. These timers are categorized into 5 groups depending upon the time base and type of timer as :- T0 - T199 timers works as Done bit of TON timer (time base-100ms). T200 - T245 timers works as Done bit of TON timer (time base-10 ms). T246 - T249 timers works as Done bit of retentive timer (time base- 1 ms). T250 - T255 timers works as Done bit of retentive timer (time base-100 ms). T256 - T511 timers works as Done bit of TON timer (time base- 1 ms). You may be aware of the working of the TON timer and RTO timer, which works similarly of TON and Retentive timers in AB PLC, the only difference is you only get the done bit of timers in mitsubishi PLC. To enter proper preset value to the timers of various time bases we need to convert the seconds into the respective time bases. Below table shows the conversion of pre-set values into the respective time bases. We can use the sa

There are total 14 instructions under the bit logic instruction like NO contact, NC contact, SR flip-flop, RS flip-flop,invert power flow etc. lets see the detailed use of them.  A) Normally open contact :- Normally open contacts are closed when the bit value stored at the specific address is equal to 1 (one)(here the specific address refers to the address assigned to the NO contact), when we press the Normally open contact assigned to the specific address then it becomes functionally closed and we get supply. here in below fig. when we press the NO contact I0.0 then Output Q0.0 gets ON and when we release the input I0.0 then Output gets OFF. B)Normally Closed Contact :- Normally closed contacts are closed when the bit value stored at the specific add, i.e. the address assigned to the NC contact is equal to 0(zero). when we press the Normally closed contact assigned to the specific address then it becomes functionally open and supply is cuts off. NC contact works e

Basically there are three main differences in Alarm and Event in SCADA system. Alarm :- It is a type of notification to inform operator about process activity & alarm represent warning of process condition that could cause problem in a system.Alarm shows notification for critical condition in a process. It require operator response as it is concerned with notification of fault in a system. A typical alarm is triggered when a process value exceeds a user defined limit or set point, such as analog value exceeding higher limit. Events :- It is also a kind of notification to inform operator about process activity but it represents normal system condition. It does not require operator response as it is concerned with normal operating condition of system. A typical event is triggered when a certain system condition is happened, such as operator logging into intouch system. so these are some basic differences in Events and Alarm in Intouch Wonderware SCAD

In this article i am going to show you how you can configure your simatic manager software for simulation. In addition i will tell you how you can change your ladder program in to 1) statement list 2) Function block. So let's start with first part- configuration of simatic manager for simulation. Step 1 : open the simatic manager. Step 2 : Close the wizard window. Step 3 : Create a new project by = File >New Step 4 : It will pop up new project window, now give name to your project and click on OK Step 5 : Double click on to the simatic 300. Step 6 : Now click on the hardware and start configuration of hardware. Step 7 : first add a rail into your hardware and add the Power supply, CPU, and SM module cards at slot no 1,2,4 respectively. you can add various SM module cards from slot 4 onward  Step 8 : now come into simatic manager window and click on blocks and then click on OB1, and then choose a programming langua