Modbus - Read and write

[davidoc85]

I was doing some testing on the modbus node and it seems like there are two issues.

1. When trying to write a value sometimes it doesn't work, and on some systems it does. I think this has to do with the function code that the modbus-serial is trying to write with.

2. When reading values and timeout occurs, the values then get queued up and then after a while all come through at once. How big is the queue? The driver should be able to manage the read and write requests with with a response timeout value and a polling interval. How is this managed when there are several points (around 60)?

[davidoc85]

Code attached in text file and preview as an image below:

nodesserial.txt

[davidoc85]

When testing with an external software, the following commands are sent. What are the function codes set by default when trying to write?

Command to send: in order to change value to 105
2017/03/06 14:30:46 >>> 02 06 00 80 00 69 48 3F
2017/03/06 14:30:46 < 02 06 00 80 00 69 48 3F

Command to read:
2017/03/06 14:31:11 >>> 02 03 00 80 00 01 85 D1
2017/03/06 14:31:11 < 02 03 02 00 69 3C 6A