Required Serial Port Send and receive data Edge Workflow

i did the following steps but my edge workflow’s debug session not triggered.please help
me if i missed anything.

step 1. I have install losant edge agent in my laptop (Ubuntu OS).
step 2 . I have cofigured gateways deviceid,accesskey,secret key in config.toml file.
step 3: after I run conainer ,my gateway connected in losant.

step 4:i have created energymeter device ,it was connected via gateway

step 4 :i have created edge work flow for energy meter.

step 5: i have deployed the workflow through gateway to device.

step 6: after I run the conainer I got below message.

in gtkTerm if i send any hexadecimal data it will give output hexadecimal data.
same i want in our Edge work flow.
Here i have attached gtkTerm screenshot.

i have sent energymeter voltage in hexadecimal format like below.

then i have received voltage output from gtkTerm like below

same thing i want in our Edge work flow.kindly help me.

but my debug session not triggered like below.

Sivasankari S

Hi @sivasankari_s,

It looks like the Serial Trigger could be the problem as the workflow does not seem to fire, and your “Write After Port Opens” value is not actually written. To begin debugging, I would recommend connecting your Serial: Write and Debug Node to a Virtual Button, and firing when the device is connected. This will allow you to see where the problem is arising. If you are able to write to your serial monitor, it will be evident that the problem lies in the configuration of the Serial Trigger.


Thanks julia.
really your message was super helpful for me.
I have used timer node instead of virtual button.It gave me a permission denied error.
after that i have fixed that issue.
now serial write node is working fine.

now I want to read my serial port data using edge work flow.which node I should select?
because we are having only serial write node.

Hi @sivasankari_s,

The Serial Trigger Node will read in data to your workflow once the device receives enough data via Serial to satisfy the configured trigger. You can read a bit more about the Serial Trigger in this Platform Update.


Thank you Julia.
I am trying serial trigger at the same time if you have any samples edge workflow
for serial write and serial trigger kindly share me.

Sivasankari S

Hi @sivasankari_s

Because Edge Workflows are generally very specific to a device or an environment, it’s challenging to generate ”samples.”

But, we have talked about doing this. I would love to hear more about what you expect out of some samples workflows, and maybe we can provide something similar in the future.

Hi anaptfox,
Thanks for your prompt reply.
I did the following steps for serial port communication.

I am using energymeter via USB and my port is ttyUSB0.

1.My Edge work flow.

2.Serial Write Config.

3.Serial Trigger(Read) Config.

4.Timer Debug

In the above Steps I got result “serialResult:true”.
Which means serial write operation was successful in ttyUSB0.

My Energymeter voltage value is “0A 03 00 81 00 02 95 58”(Hex)
if write this to serialport(ttyUSB0) the energymeter should give the voltage.But serial trigger node didn’t trigger for my edgeworkflow.
if i did anything wrong or should i change my steps,please share me.
Sivasankari S