Hi,
I need all the assistance I can get.
SCENARIO:
I am going to be using an analogue module for the first time.
The PLC is S7-226 with a Analogue module with 1-IN/4-OUT.
I am going to use a Weighing module to give me 4-20ma.
This W/module gets data from 4 load cells, which I will engage and disengage, using a Air Cylinder.
APPLICATION (OPTION 1): (Analogue 4-20mA)
I'll skip the unneccesary details.
I need to enage the LOADCELLS, so that I start getting the reading from the Analogue moduel, this will be the TARE weight (TARE is total of the patform + conveyor + the empty carton that moves on to this conveyor)
Then I start feeding the carton, and monitor the reading until the desired is achived. shut of the hopper and move the conveyor to bring in the next carton.
ONE THING TO REMEMBER IS, I WILL NEVER BE REQUIRED TO CHANGE THE NET WEIGHT. to clarify, I would say this is not a PID kind'a environment, as all I do will be to turn ON and OFF, the hopper (feeder). (Strictly no Analogue outputs!)
APPLICATION (OPTION 2): (Digital output)
The Metler Toledo guy has also offer a mini-controller with 1-IN/3-OUT. what I was planning to do was use this. why? read on and advise if I am thinking correct.
same application, the carton comes and PLC engages the loadcells, and gives the INPUT to weight controller, which in turns 'ZERO's the counter, I start pouring in the product, until the Controller it self gives me the Digital output, so that I can turn of the hopper.
Advantages:
1) I will evade the Analogue programming, de-bugging, ......
2) still the use has the option to increase or decrease the preset value.
3) Analogue module is expensive, I save money too.
One last thing, since the application does not require a PID programming, just need to monitor the ZERO (x mA) and final (xx mA). do some maths, and I have the result.
The only dis-advantage I see is, if I program the PRESET weight (in mAmps) within the program, the user can never change it, and if want to program it in such a way, that the Preset can be defined, in the HMI, this means more work.
and hey! dont start thinking, I'm afraid of Challenges, but time is short and I have to finish the procurement & installation of all Elec.'s in next 20days. (wish me luck)
.... more questions later.
I need all the assistance I can get.
SCENARIO:
I am going to be using an analogue module for the first time.
The PLC is S7-226 with a Analogue module with 1-IN/4-OUT.
I am going to use a Weighing module to give me 4-20ma.
This W/module gets data from 4 load cells, which I will engage and disengage, using a Air Cylinder.
APPLICATION (OPTION 1): (Analogue 4-20mA)
I'll skip the unneccesary details.
I need to enage the LOADCELLS, so that I start getting the reading from the Analogue moduel, this will be the TARE weight (TARE is total of the patform + conveyor + the empty carton that moves on to this conveyor)
Then I start feeding the carton, and monitor the reading until the desired is achived. shut of the hopper and move the conveyor to bring in the next carton.
ONE THING TO REMEMBER IS, I WILL NEVER BE REQUIRED TO CHANGE THE NET WEIGHT. to clarify, I would say this is not a PID kind'a environment, as all I do will be to turn ON and OFF, the hopper (feeder). (Strictly no Analogue outputs!)
APPLICATION (OPTION 2): (Digital output)
The Metler Toledo guy has also offer a mini-controller with 1-IN/3-OUT. what I was planning to do was use this. why? read on and advise if I am thinking correct.
same application, the carton comes and PLC engages the loadcells, and gives the INPUT to weight controller, which in turns 'ZERO's the counter, I start pouring in the product, until the Controller it self gives me the Digital output, so that I can turn of the hopper.
Advantages:
1) I will evade the Analogue programming, de-bugging, ......
2) still the use has the option to increase or decrease the preset value.
3) Analogue module is expensive, I save money too.
One last thing, since the application does not require a PID programming, just need to monitor the ZERO (x mA) and final (xx mA). do some maths, and I have the result.
The only dis-advantage I see is, if I program the PRESET weight (in mAmps) within the program, the user can never change it, and if want to program it in such a way, that the Preset can be defined, in the HMI, this means more work.
and hey! dont start thinking, I'm afraid of Challenges, but time is short and I have to finish the procurement & installation of all Elec.'s in next 20days. (wish me luck)
.... more questions later.