Setting Device Power and Read Mode about python-mercuryapi

[gotthardp]

Hello. The python wrapper currently implements only a very small portion of the mercuryAPI because I didn't want to implement functions that nobody needs. There is currently no way to set the device's power and read mode, but I can easily implement those for you.

Could you please describe a bit more what exactly you need?

• You want to set /reader/radio/readPower or /reader/powerMode?
• You want to set pseudo-acynchronous or continuous reading, or you meant something different?

[eheaton]

Hi @gotthardp - Thanks for the reply. To answer your questions.

• We're looking to set the /radio/read/power.
• Correct. We're looking to set the pseudo-async, continuous reading

[gotthardp]

Hi @eheaton, few more questions please:

• You mean /reader/radio/readPower, right? Will an single integer parameter in set_read_plan do the job you need? E.g. reader.set_read_plan([1], "GEN2", power=10)?
• Do you have any thoughts on how the async-read should be architected? How shall the main loop look like? What makes the synch read() not suitable for your project?

[eheaton]

Sorry, yes - I meant /reader/radio/readPower ... the single int would be perfect.

As far as the sync read method, we're looking for a way to keep the reader in a continuous state to always be looking for tags once they get close. We currently have it looping over the read function every X seconds, which isn't bad, but we were under the impression that there's a mode you can put the reader in to do this natively.

[ENAML]

Hey @gotthardp,

Thanks for adding this functionality! I've been trying to get your updates working, but I'm encountering what I believe to be an error in how the "set_read_plan" method in Python is passing arguments to C. See below:

Traceback (most recent call last):
  File "read.py", line 12, in <module>
    reader.set_read_plan([1], "GEN2", 1900)
RuntimeError: More keyword list entries (3) than format specifiers (2)

Would you mind taking a look at this? I've tried recompiling after making tweaks to "Reader_set_read_plan" in C but nothing seems to have worked. Thanks again!

[gotthardp]

you should specify the keyword, i.e. do reader.set_read_plan([1], "GEN2", read_power=1900)

[ENAML]

I'm still getting the same issue after changing it:

Traceback (most recent call last):
  File "read.py", line 12, in <module>
    reader.set_read_plan([1], "GEN2", read_power=1900)
RuntimeError: More keyword list entries (3) than format specifiers (2)

edit: this is the code causing the issue:

import sys
import time
import mercury

print("starting reader script")

reader = mercury.Reader("tmr:///dev/ttyUSB0", baudrate=115200)

reader.set_region("NA")
reader.set_read_plan([1], "GEN2", read_power=1900)

print(reader.read())

[gotthardp]

My bad, sorry for that! (I don't have the reader today so I was unnable to test it.) Try now again, please.

[gotthardp]

It should work now. Please do git pull and try it.

[gotthardp]

Hi again. Any success with this issue?

Please note that I did some more updates and reader.read() now returns a list of objects rather than the list of tuples.

[gotthardp]

I assume everything is OK.