Using the analog inputs on a Micrologix 1000 Analog

Hello. I have a project due in which first, I have built a DVM. Next, I have to interface it with a PLC. The voltage ranges are 0--1.9V and 0--19V. I was thinking of connecting leads from the DVM to the analog input of the PLC, but not quite sure how this would work. Also,unsure of how to write a program to make the PLC "read" the DVM and display an output. Any help would be greatly appreciated. Thanx

Whats the output of the DVM?

The first thing we need to know is the design of your DVM. A schematic would be nice. While you could get by with sending the voltage to an analog input of the ML1000, you can't guarantee that both the DVM and ML1100 will always read exactly the same. A more elegant/correct solution would be to send the displayed digits of the DVM to your plc. Are you using a DVM chip or some sort of microcontroller.

Thanks for you reply.

The DVM is made of ply-wood and 2 seven-segment displays made of Christmas lights. Don't laugh, this is a graded project. The leads of the DVM have to be interfaced with a PLC. Building the DVM was the easy part, but I have no idea how to connect the two together. Looking at this MicroLogix 1000 Analog, I see an analog output measuring DC voltage and an analog input that can vary the voltage from 1 to 9. The input section of the PLC has two screws labeled analog input and output. Is it possible to connect the leads of my DVM to these inputs getting it to "read" the DVM? So far, this is what I've come up with. Thanks.

Does your design use a chip that is converting a hex number to a 7 segment display? If so you could read the hex numbers using 8 input lines on your plc. You would need to develop a circuit to raise the logic levels to a level accepted by the the plc - preferably using an optocoupler.

If your deadset on going the analog route, take a look at the analog inputs specs in a manual - you need to learn to dig this stuff out. Depending on the input range you might need to scale down and/or offset the voltage using one or two op amps. What about two resistors to form a voltage divider. Sorry, but I will only give you hints.

The Ml1000's analog inputs read (accept) voltage or current from an external source. The ML1000's analog outputs will output voltage or current to an external device.
Again does your DVM have a output? Or are you trying to output a voltage from your ML1000 to your DVM?