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ISISComputingGroup / lewis-ess

Let's write intricate simulators!
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Binding devices attributes via modbus #281

Open KacperKlys opened 4 years ago

KacperKlys commented 4 years ago

Hi guys,

In the documentation file it is written that:

class ModbusBasicDataBank does not support binding addresses to attributes or functions of the device or interface.

So my question is what does support binding mechanism in case of modbus. In the example on github, there is only interface layer with ModbusBasicDataBank which initializes addresses and values. How I can get data from simulated device via modbus?

DominicOram commented 4 years ago

Hello,

We have an example of how to create a modbus device here. The interface.py is setting up the Modbus interface with which registers to use and device.py will populate those registers. I hope that example helps, if it doesn't please let me know and I'll write a more basic example.

KacperKlys commented 4 years ago

Hi Dominic, Basing on the link you sent me I tried to do something on my own. Unfortunately, I think i'm still missing something since I can't get rid off one error. My short project is made of one file chiller.py. Problem is in line 43 in chiller.py -

Chillerdevice has no attribute interface

Here is my code

DominicOram commented 4 years ago

Hello @KacperKlys. I've taken your example and got it to work in https://github.com/DominicOram/LewisExample.

The main issue was that you need to manually assign the interface to the device so that it has a reference. This may make sense as something the framework does for you, I'll have a think about adding it.

I also fixed a couple of minor typos in your device, it should all now work fine. Please let me know how you get on. Out of curiosity what is the device that you are emulating? We should probably come up with a shared set of common devices.

KacperKlys commented 4 years ago

Hi @DominicOram ,

I have created first version of my device's simulator ChillerSimulator. I would be grateful for any comments or tips.

I still have some questions. I thought that the idea of this framework is to have seperated layer of device and layer of ccommunication so we can create different types of interfaces for the particular device without changes in the code of device. In this case, the communication layer is associated with the device. Is there any way to rewrite this code to seperate those layers?

Answering your question, this is chiller for control system of lasers, this device will be connected via modbus and then controlled by EPICS.