Windows Modbus Reader

So, to be honest I'm brand new to the PLC world. I'm basically a software support guy for Windows who got wrangled into doing some extra stuff for the company. Long story short, I'm confused about modbus, how it works, and how to utilize data. I have a USB to RS 485, and I need to just be able to see the data coming in on a Windows PC in an easy to understand layout. I would really appreciate any help at all. I'm so in over my head and stressed out. I believe it's set up for two wire (with one shield cable), and it has terminal screws. I downloaded modscan, but it doesn't mean anything to me. I understand (vaguely) that it is hex that I'm seeing, but I need to know real numbers that make sense. For instance, I know RPM is (for example) register 32. I need to be able to see a list of selected registers and go "oh okay, so register 32 says 1800, so I know the engine's RPM is at 1800." If that makes sense. I'm sorry, I'm trying my best, and my job may be on the line. It's a lot to take in, and we basically got shoved into this mess last second when our telemetry supplier went belly up.
Modscan is a great tool for checking, confirming and troubleshooting a Modbus connection and the data format, but it might not be the right tool for displaying data on a continuous, operational basis. A SCADA or HMI software package with a Modbus driver might be more what you need because those packages are designed to have an operational data display mode, rather than a troubleshooting data display.

But to get the values viewable with what you are now working with, here's some hints.

You need to data view, not the traffic because you're nopt interested in traffic, you just want the data and the traffic view is always in hexadecimal. The screen shot below with the highlighted traffic button shows the traffic stream in hex.

0c Show Traffic-with traffic-hi.jpg

Picking the Data view (data button) just shows address registers and their associated data values:
0b Show Data - FP-hi.jpg

You can also select traffic or hex displays from the drop down menus under Setup:
Display options - traffic or data.JPG

In the data view, there is a choice of number formats, binary, hex, decimal, integer or a choice of 2 floating point formats, as shown on the display options menu in the screen shot above. The four data values shown above are in hexadecimal format.

The two data values shown below are in one of the floating point formats, but selecting one of the other format buttons will change the displayed value format.

format is one of two Floating Point formats-Swapped FP button Hi.jpg

Note that there are no engineering units. SCADA and HMI software package allow for a setup with engineering units that are displayed with the updating data values.

Modbus is a protocol that is responsible for getting bits from one device to another. Modbus does not know or care what the data represents or how it is to be interpreted, it just carries bits. It's up to the higher level application software (Modscan in this case) to interpret the bits and associated information, like scaling for graphing or engineering units, or for logging the data. If you poke around the Modscan Help file you'll find some means of capturing a text file as a means of logging the data. Trending the data takes an additional license.