SNAP PACK R2 as Modbus TCP/IP salve


#1

Hi support team

We are using Snap pack R2 Controller with 32 channel Analog Inputs. I want to use Snap pack R2 controller as Modbus TCP/IP slave. I configured all Analog Inputs and also gone through [B]“PACModbusSalve”[/B] subroutine but couldn’t get the data.:confused::confused:

My Configuration

ch1 - input type 4 to 20 mA. High Limit - 80, Low Limit - 20

As per above given configuration kindly provide the Modbus mapping or kindly guide me to how to use PACModubusSalve subroutine for above given configuration.

Thanks in advance.


#2

[LEFT]If you only want to read analog inputs you can use the built in Modbus. Are you aware it is bult in?[/LEFT]
[LEFT]If you need other data from the strategy then the Modbus integation kit can be used. The slave subroutine is included.[/LEFT]
[LEFT] [/LEFT]
[LEFT]To use the kit there is a setup to set data type and communication handle.[/LEFT]
[LEFT]The data type for a float is 2 or 3.[/LEFT]
[LEFT]The analog inputs values will need to be moved into the holding register 4x float table.[/LEFT]


#3

Hello visarg,

Welcome to the OptoForums! The built-in Modbus support mentioned by tmcculloh simply maps our memory map (any your analog input values each have a memory map address for them) to a Modbus address, as mentioned in this post:
http://www.opto22.com/community/showthread.php?t=638&page=1
and in our [B]OptoMMP (memory map protocol guide, form 1465)[/B].

Also, don’t forget that our [B]Product Support is FREE[/B] and they’d be happy to help you.

-OptoMary


#4

HI there…

Thanks for the reply…

How to move analog input values to Holding register 4x float table…


#5

You don’t actually have to move any values, they’re already in the registers automatically, you just need to calculate the Modbus address that corresponds to the memory map address (as shown in the links mentioned above).

Here’s an analog input example:

First I need to find the memory map address of the point I’m interested in. I can do this using form 1465 (link in my previous post) or by using PAC Manager.

For this particular example, I’m using the temperature from my ICTD module in position 3 (point 0), which is memory map address F0263000:


Now I can use the PAC Manager’s Modbus Calculator to find the corresponding Modbus address, to see that address F0263000 corresponds to Modbus Unit ID 21, register address 6144:


Then I just plug those values into my Modbus data scanner and I can see that Analog Input value!


It’s just that easy!

-OptoMary