Chris B
Member
Hello,
I'm trying to find a controller, PLC or otherwise, to run a machine I'm helping develop for the wood products industry. My questions are:
1. Can a PLC store a series of 30 or so binary words? Each of the 16 bit words represent the L/W/H dimensions of one piece of lumber. The lumber is on a conveyor and there may be anywhere from 1 to 30 pieces of lumber between our tool and the machine providing the dimensions. If the answer to this question is no then don't trouble yourself to read any further.... but plaese post if this is a no.
2. This question is a little more difficult to ask and explain. Our tool weighs each piece of lumber and comes up with the Measured Wet Weight. Using the dimensions sent to our controller in the binary format mentioned in question 1 I need to calculate the percent moisture content of that piece of lumber. Basically:
MWWL = Measured Weight Wet Lumber (lbs per cubic foot)
KWDL = Known Weight Dry Lumber. ( " )
((MWWL-KWDL)/KWDL) * 100 = %MC
The KWDL value is a constant dry weight of one cubic foot of bone dry wood of a particular species. Depending on the species of wood being weighed each time, a different dry weight value needs to be substituted into the %MC calculation for KWDL.
Q 2: Can a PLC store a table of values like one of the following tables?)
White Cedar: 18.4
Red Cedar: 17.9
Oak: 45.2
RedwoodOG: 29.52
RedwoodNG: 28.3
or if I can't use characters:
1: 18.4
2: 17.9
3: 45.2
4: 29.52
5: 28.3
Normally this table would be one where the operator would select a species of wood at the beginning of the process and the same KWDL value is used in every calculation. However, I would like to have four bits coming into the controller that are appended to the binary string for the dimensions that signify which species of wood my tool is weighing and then use the appropriate dry weight value from a table stored in the PLC software.
I think it's now obvious to you after having read these questions that I know next to nothing about PLC's. If the answers to these questions are yeses then I'll be going to the local college to learn about PLC's. For now, all I need to know is if a PLC can operate like this...before I jump feet first into a class that would be useless to me. I have very limited experience with BASIC and C++ programming.
Anyway, thanks for the long read and thanks for your answers.
chris.
I'm trying to find a controller, PLC or otherwise, to run a machine I'm helping develop for the wood products industry. My questions are:
1. Can a PLC store a series of 30 or so binary words? Each of the 16 bit words represent the L/W/H dimensions of one piece of lumber. The lumber is on a conveyor and there may be anywhere from 1 to 30 pieces of lumber between our tool and the machine providing the dimensions. If the answer to this question is no then don't trouble yourself to read any further.... but plaese post if this is a no.
2. This question is a little more difficult to ask and explain. Our tool weighs each piece of lumber and comes up with the Measured Wet Weight. Using the dimensions sent to our controller in the binary format mentioned in question 1 I need to calculate the percent moisture content of that piece of lumber. Basically:
MWWL = Measured Weight Wet Lumber (lbs per cubic foot)
KWDL = Known Weight Dry Lumber. ( " )
((MWWL-KWDL)/KWDL) * 100 = %MC
The KWDL value is a constant dry weight of one cubic foot of bone dry wood of a particular species. Depending on the species of wood being weighed each time, a different dry weight value needs to be substituted into the %MC calculation for KWDL.
Q 2: Can a PLC store a table of values like one of the following tables?)
White Cedar: 18.4
Red Cedar: 17.9
Oak: 45.2
RedwoodOG: 29.52
RedwoodNG: 28.3
or if I can't use characters:
1: 18.4
2: 17.9
3: 45.2
4: 29.52
5: 28.3
Normally this table would be one where the operator would select a species of wood at the beginning of the process and the same KWDL value is used in every calculation. However, I would like to have four bits coming into the controller that are appended to the binary string for the dimensions that signify which species of wood my tool is weighing and then use the appropriate dry weight value from a table stored in the PLC software.
I think it's now obvious to you after having read these questions that I know next to nothing about PLC's. If the answers to these questions are yeses then I'll be going to the local college to learn about PLC's. For now, all I need to know is if a PLC can operate like this...before I jump feet first into a class that would be useless to me. I have very limited experience with BASIC and C++ programming.
Anyway, thanks for the long read and thanks for your answers.
chris.