Hello,
I am relatively new to PLC's and water treatment. I currently working in a water treatment facility as an instrumentation worker. I have unable to understand the logic that is setting the analog output to our lime slurry making machine. I have about 90% understanding there is just 1 static # in the path that does not make any sense to me. I will try to describe it. We are using Modicon Quantum PLC's.
First block is multiply integer block. It takes the dosage which is a value that is operator input and multiplies by the un-scaled value of the selected flow device(DP x-mitter and flow tube)
second block is another multiply integer block. This is where the mystery # comes in. It takes the product of block 1 and multiplies it by the static # 69,508. This value is not referenced anywhere else in logic, so I assume the original logic architect placed this here for a reason.
3rd block is a DIV floating point by integer. Here it takes the product of block 2 and divides by the # 2000 which represents the maximum lbs of lime the belt feeder can handle per hour.
4th block same as 3rd. It divides the product of #3 by the purity of product which 92% pure but is actual # in register is 92
5th is same as 3 and 4th. This block divides the product of #4 by 10
any thoughts what the 69,508 # could be. In this industry the normal chemical feed formula typically used is:
FeedRate,Lbs/day=
(dose,mg/l)(flow, MGD)(8.34lbs/gal)
----------------------------------------
Chemical purity % expressed as decimal
Thanks,
I am relatively new to PLC's and water treatment. I currently working in a water treatment facility as an instrumentation worker. I have unable to understand the logic that is setting the analog output to our lime slurry making machine. I have about 90% understanding there is just 1 static # in the path that does not make any sense to me. I will try to describe it. We are using Modicon Quantum PLC's.
First block is multiply integer block. It takes the dosage which is a value that is operator input and multiplies by the un-scaled value of the selected flow device(DP x-mitter and flow tube)
second block is another multiply integer block. This is where the mystery # comes in. It takes the product of block 1 and multiplies it by the static # 69,508. This value is not referenced anywhere else in logic, so I assume the original logic architect placed this here for a reason.
3rd block is a DIV floating point by integer. Here it takes the product of block 2 and divides by the # 2000 which represents the maximum lbs of lime the belt feeder can handle per hour.
4th block same as 3rd. It divides the product of #3 by the purity of product which 92% pure but is actual # in register is 92
5th is same as 3 and 4th. This block divides the product of #4 by 10
any thoughts what the 69,508 # could be. In this industry the normal chemical feed formula typically used is:
FeedRate,Lbs/day=
(dose,mg/l)(flow, MGD)(8.34lbs/gal)
----------------------------------------
Chemical purity % expressed as decimal
Thanks,
