continuously batch procces exercise ..

dagash · Dec 18, 2011

hi ...
i am trying to make another excersices with ( batch process ) simultion in Logixpro .

my idea concept is without using ( counter + timers ) to design a program to meet the folloeing requiremts :
1- fill the batch tank with pump 1 only . ( no mixturing here )
2- when the tank was full pump 3 must be open to drain the tank .
3- pump 1 and pump 3 are not working together .
4- when we start the simulation by using start bottun system must fill and drain contiuously , and stop just when we push the stop bottun .
( counter + timers + flowmeter + thermostate + mixer )can not be used.
that is my try , but im having difficulty to make it work continuously .

Lancie1 · Dec 18, 2011

Dag,

Your program as specified uses basic programming techniques.

You must think about your overall logic and set up a SYSTEM RUN relay using O:2/5.

Then use a stage, condition, or step relay to tell you when the tank has been filled.

You can use only one step relay, but I left in the 2nd one because you will need it when you add the Mixing Cycle in the next student exercise. Always look ahead to what may be coming.

dagash · Dec 19, 2011

I need more information about ( output latch and output unlatch )

Lancie1 · Dec 19, 2011

You can look at any instruction in the LogixPro "Help, Rockwell RSLogix Instruction Help" file.

OTL [Output Latch]
Description
This instruction functions much the same as the OTE with the exception that once a bit is set with an OTL, it is "latched" on. Once an OTL bit has been set "on" (1 in the memory) it will remain "on" even if the rung condition goes false. The bit must be reset with an OTU instruction.

Latch and unlatch instructions must be assigned the same address in your logic program. Output addresses are specified to the bit level.

Note: In the event of a power loss, any OTL controlled output device will energize with the return of power if the OTL bit was set when power was lost.

OTU [Output Unlatch]
Description
Use this output instruction to unlatch (reset) a latched (set) bit which was set by an OTL instruction. The OTU address must be identical to the OTL address which originally set the bit.

If your instructor will not let you use Latch and Unlatch, you can make the step relays self-sealing or self-latching, as shown.

dagash · Dec 20, 2011

ok , thank you for informations .

take this solution ( just by using NC & NO ) without ( latch & unlatch output ) , also notice this point it is smaller than yours ... ^_^

dagash · Dec 20, 2011

there is another exercise .
# exercise 2 :
without using ( counter + timers ) to design a program to meet the folloeing requiremts :
1- fill the batch tank with pump 1 only . ( no mixturing here )
2- when the tank was full pump 3 must be open to drain the tank .
3- pump 1 and pump 3 are not working together .
4- after tank is empty , pump 2 start to fill the tank again .
5- then pump 3 work to drain .
5- when we start the simulation by using start bottun system must fill and drain contiuously ( pump 1 -> pump 3 -> pump 2 -> pump 3 , then repeat the cycle ) , and stop just when we push the stop bottun .
- each pump cant work with another pump at same time .
- ( counter + timers + flowmeter + thermostate + mixer )can not be used.

* after you solve it , try it again by using ( latch and unlatch output ) .

Lancie1 · Dec 20, 2011

also notice this point it is smaller than yours ... ^_^

Sorry, but I did not realize we were having a contest. I was not going for "smaller" but easy-to-use and change, also easy to modify for the other LogixPro Advanced Batch Mix Exercises.

For PLC programs, small is not always better, because in most cases, someone else is going to be looking at your program and trying to understand how it works and how it can be modified and how other functions can be added.

If you want to go smaller, then delete the I:1/0 START pushbutton from your Rung 001. With the System Run relay, you only need ONE start pushbutton for the entire project.

As far as your exercise to add Pump 2, that is a trivial problem. Here it is on one rung. This is SMALL, but (1) it is hard to understand, (2) it is hard to change, (3)the electrical maintenance men will cuss you out for this.

dagash · Dec 20, 2011

Hi again .. ^_^

For PLC programs, small is not always better, because in most cases, someone else is going to be looking at your program and trying to understand how it works and how it can be modified and how other functions can be added.

if someone can do this procedures definitely he can understand my solution ..
again .. comments make our commend easy to understand ..

If you want to go smaller, then delete the I:1/0 START pushbutton from your Rung 001. With the System Run relay, you only need ONE start pushbutton for the entire project.

but this will make the tank is filled again before it is discharged ( drain ) --> thats happend when we push start after we push stop during cycle operation .. >> try it
but also it is not false , sometimes we need to discharge the tank before any operation and sometimes we can contineu filling in spite of remaining liquid on the tank .

(3)the electrical maintenance men will cuss you out for this.

if he did i will kick him outside .... loool

Lancie1 · Dec 20, 2011

but this will make the tank is filled again before it is discharged ( drain ) --> thats happend when we push start after we push stop during cycle operation .. >> try it

No, no, you have to adjust the other logic also to allow ONE set of pushbuttons. Because you like SMALL programs, try these two working one-rung versions.

Lancie1 · Dec 20, 2011

One rung alternating Pump 1 and Pump 2.

dronai · Dec 20, 2011

Lance, because there are no timers, or counters, I would need to switch the float switches manually, to run this program continously yes ?

I loaded the OP's program last night, and it did seem to have redundant switching. Tonight I'll load yours.

dronai · Dec 21, 2011

Lance your program rung 2, the latch output (B3:0/1) will not latch, nor will rung 3 contact B3:0/1 toggle ?

I didn't think on my program you can have 2 outputs on a rung. A latch is considered a output yes ?

dagash · Dec 21, 2011

Lance, because there are no timers, or counters, I would need to switch the float switches manually, to run this program continously yes ?

I loaded the OP's program last night, and it did seem to have redundant switching. Tonight I'll load yours.

dear dronai
firstly , we just try here to gain more experience with limited abilities .

also we will contineu solve problems like those without ( timers and counters and shift registers ) until the last possible idea .

dagash · Dec 21, 2011

Lancie1

No, no, you have to adjust the other logic also to allow ONE set of pushbuttons

give more explaination here ...

i will try your program in post #10 , its work correctly in the first time i do , but when i save it and again load to try it again something happened to ( logixpro ) , some options and bottuns disappeared and when i minimize the screen and maximize it everything looks good , but when i run the program ( PUMP 2 start firstly ...!)

dagash · Dec 21, 2011

are there any programs have a batch simultion experiment...?
do you advice me with another programs ...?

continuously batch procces exercise ..

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