## tenths, hundredths?

## tenths, hundredths?

(OP)

I'm in the conception phase of a new project and wondering if I can use a PLC as the control device. I need to measure the opacity of a solution, most likely using a diode-receiver pair with a proportional voltage output. My question is how precise of a measurement can I obtain with a plc analog card (how many decimal places) one would be fine, two would be optimum. Can anyone sequence me through the steps of obtaining decimal places from a BCD value? I'm fairly familiar with ladder logic however this would be my first time dealing with an analog input.

I would most likely use an Automation Direct DL06 PLC with a F0-2AD2DA-2 Analog Combination Card.

Thanks in Advance for any assistance,

Pete

I would most likely use an Automation Direct DL06 PLC with a F0-2AD2DA-2 Analog Combination Card.

Thanks in Advance for any assistance,

Pete

## RE: tenths, hundredths?

## RE: tenths, hundredths?

The objective of the system is to measure the nickel concentration of a plating solution. The concentration of a nickel plating solution is measured in g/L, with 6 g/L considered a 100% concentration. The color of a 100% Nickel plating solution is a deep green and lightens linearly with a decrease in concentration. I have already proven that I can obtain a linear voltage output throughout the practical concentration rage of 60 to 100%.

I've been trying to display measured voltages on an Automation Direct EZTouch Panel in two different ways; in grams per litter (0.00-6.00 g/L), and in concentration percentage (0.00-100.00%). I'm failing miserably at both

The Touch panel programming software lets you pick the data type (integer, BCD, BIN, OCT, etc), digits to display (1 -5) and also how many fractional digits to display. However, lets say I'm displaying the number 4, and would like it to be displayed as 4.0, I choose "BCD", "display two digits" and "1 fractional digit" in the program but it displays the value as 0.4 not 4.0...

If anyone has any idea what I'm talking about I would greatly appreciate some guidance :)

## RE: tenths, hundredths?

or m=6000/4095 or m=1.465. m ~~ 146/100. In integer math I would mult raw data by 146 and then divide by 100 to keep the accumatolor from puking. This example wasn't well thought out because of the large number problem; but, you see that when I have 1526 in the display register, it represents 15.26 ips. If you want to use a EZ panel your register MUST contain your data X10 for tenths display or X100 for hundreths display. I hope this helps you in your work. Holler if it doesn't

## RE: tenths, hundredths?

## RE: tenths, hundredths?

Sorry it has taken me so long to reply but I live in the northeast and we just got hammered with 30 inches of snow...

Anyway thanks for the info...I'll see what I can do with it. If you can help me a little more that would be great.

This is what I have, and what I need done:

(1) I'm using the card at a 0-5V input

(2) I need displayed 0.0 - 10.0 g/L

## RE: tenths, hundredths?

1st take a reading of 0.0g/l solution and the raw value in is your zero or b that we want to subtract from the raw value.Write a line that takes RAW DATA in and subtracts b from the RAW DATA and places in in a register called 'zerod'. Next having done that, take a reading of 10.0g/l solution and look at value in 'zerod'. Your scale factor must divide into 'zerod' and result in 100. Place the result in a register called 'Display'. That's all there is to it. I'm assuming that you have experience with subtract, mult, and divide blocks. Try this and write back if you have any problems with overflow or what have you. This technique you should learn as it is the one I always use to calibrate scales, displays, or data aquisition systems. Hope this helps.