modbus transfer string value

[asherb]

hello,

i have a question about the modbus, we have a string value, we want to have it in rapid scada. i tried addressing the value, but it shows up as a number in rapid scada. i am wondering how could transfer string value from plc to rapid scada via mdobus.

thanks!

[manjey73]

As far as I understand, you need to combine several registers into an array and specify a channel with the required data length. And in the Format to indicate that this channel is UNICODE or ASCII.
I haven’t tried it myself yet, but it seems like this is how you need to work with strings

[Mikhail]

Hello,
What is the max. length of the string?

[asherb]

hello Mikhail,

the max length of the string is around 30.

[Mikhail]

Try getting a string as 4 registers of double type (8 bytes). They should be bound to 4 channels of the String data type. Let’s see the result.

[asherb]

hello Mikhail,

I bounded to 4 register of double type (8bytes) in rapid scada, and i tried both unicode and ascii as data type, however, it shows me as a very large number in the modbus current data list, and in the web browser, the string variable only show me ‘—‘,

please let me know what i can do for this.

thanks

[Mikhail]

Hello,
Change the channel data type to blank (double) to get large numbers.
Then add a new channel of the Calculated type, string data type and an input formula Data(101), where 101 is the source channel number.
Send screenshots of the settings and results.

[asherb]

hello Mikhail,

thank you for your help, i tried, my configuration:
https://sm.ms/image/vr5EZHQi6jToBPK

however, it shows like random things, btw, the string i have is in english, it shows like this:
https://sm.ms/image/2I8oLSBmE4lsXpa

please let me knwo how i can fix this.

thanks

[Mikhail]

Hello,

Could you try the following:
1. In Modbus template change element’s data type to ulong (8 bytes)
2. Update channel data type to Integer, and set channel format to Hexadecimal
This can help to check the actual channel values.

[asherb]

hello Mikhail,

i tried you mentioned above, however, i got a message in channel like this: https://sm.ms/image/wezHWgTs2JIN6VD

the calculated string channel shows: https://sm.ms/image/3UzKmxgHNMuToyd

the integer channel shows: https://sm.ms/image/Sy537m6tuTq4bsG

it is supposed to show this: https://sm.ms/image/JufC6ojrKMLgviE

please help, thanks

[Mikhail]

Hello,

Could you make screenshots of the channels, Modbus template, and device data (in Communicator)?

[asherb]

hello Mikhail:

modbus template and communicator: https://sm.ms/image/KCxcXisOD6Qt3p1

channel configuration: https://sm.ms/image/4bRprKFHcBWISTv

what it show right now : https://sm.ms/image/Zp6YKS83aR7CebH

how it shows in plc : https://sm.ms/image/bRiBrfy3tg6GTXM

please help

thanks

[Mikhail]

Hello,

I managed to make it work:
https://ibb.co/82BgRvJ
https://ibb.co/7nHQ7Hn
https://ibb.co/sb4vvyk
https://ibb.co/m4MdhqY
https://ibb.co/GTG0P8Z

[Mikhail]

Byte order in the Modbus template is 76543210

[Mikhail]

Currently it does not work with ulong data type. We should add this option in the future.

[Author]

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