simple weighing project/2load cells/PLC

[Sachith]

hello everyone,
i am a student and new to plcs. i have a small weighing project. in this i have to use 2 load cells, 3 pneumatic actuators. there are two hopers. 1st one controls the flow.when 1st get filled a door opens and put them into the second. using load cells i have to get the weight of the 2nd hoper. and open the door using actuators.

at the end of the day i have to display the total weight which passes through the second hopper.
i am going to use a 4 Channel Strain Gauge Sum Amplifier (http://www.aliexpress.com/store/pro...gnal-output-0-5V-4-20mA/607949_344806141.html) to load cells and input the 0-10v analog signal to plc for controlling. i want to sum all the readings and display at the end.

my questions,

1. can i use siemens logo plc (OBA6) to this project.(it has 4 analog inputs)

2. or else what is the cheap and best plc for this

3. have any one used above mentioned amplifier.

4. if some one can please send me a example ladder program which used for a weighing application like this.

 

[Lancie1]

1. Can I use Siemens Logo plc (OBA6) [for] this project? (It has 4 analog inputs).

Yes, you could use the Logo PLC.

2. Or else what is the cheapest and best plc for this?

Searching for "Cheapest PLC Controller" finds the AliExpress site where you found your load cell transducer:
http://www.aliexpress.com/store/group/PLC-Controller-Industrial-PC/718763_250098875.html

The cheapest PLC is probably not the best one for you to use. The best one to use may be the one that you have used in your student training class. The best depends a lot on your knowledge. Which PLC do you know how to program? If you have written programs for the Logo, then use that one. If you have no PLC programming experience, then look around your local area to see what other people are using nearby. That way, if you use the same PLC, you will be able to find someone to help you with problems.

3. Has anyone used the above-mentioned amplifier?

I have not used that SMOWO RW-JT4 strain gauge trasducer, but I have used other similar units. The important thing is that it will sum 2 inputs from your 2 load cells, and that you must have an external 12-to-24 volt DC power supply to use to power this transducer.

4. Will someone please send me a example ladder program which is used for a weighing application like this?

I have no examples for a Siemens PLC. I have some weighing examples for Allen Bradley SLC 500 PLCs. Usually you can find examples for different applications in the Sample file for the software that you use for programming your PLC.

 

[Sachith]

Thank you very much for your quick reply:beer: it helps a lot.

if you can please email your examples on allen bradly. so that i can get an idea.

 

[Lancie1]

Here is an example for weighing a burette (large test tube), and using the changing weight for two purposes. First, the weight is used to determine when to refill the burette from a Fill Tank. Second, the change in weight is used to set up a Loss-in-Weight control function that controls the speed of a pump that pumps the material in the burette into a process system. The loss in weight over time is calculated (every 20 seconds because only very small amounts of Wax are used, so the weight changes slowly), then scaled for two different purposes, to display on the RSView operator screen, and to use in the PID block that controls the speed of the P201 Wax Pump.