Experimental Physics and
Industrial Control System

And the mbbi record used in this demo:

   1 record(mbbi, "status") {
   2     field("VAL", 3)

   3     field("ZRST", "Level0")
   4     field("ONST", "Level1")

   5     field("TWST", "Level2")

   6     field("THST", "Level3")

   7     field("PINI", "1")

   8 }

On 2/19/19 9:25 AM, Tong Zhang wrote:
> mypv.get(as_string=True) returns the string value as expected. Please
> see the detailed constructed fully functional demo below:
>
> Script works as expected with mbbi record:
>
>    7 import epics
>    8 import time
>    9
>   10
>   11 pv_name = 'INVALID_PV_NAME'
>   12
>   13 def pv_with_callback(pv_name):
>   14     pv = epics.PV(pv_name)
>   15     time.sleep(2)
>   16     def on_value_changed(char_value, **kws):
>   17         print("Char Value: ", char_value)
>   18     pv.add_callback(on_value_changed)
>   19
>   20
>   21 pv_with_callback(pv_name)
>   22
>   23 time.sleep(2)
>   24 pv_name = 'status'
>   25
>   26 pv_with_callback(pv_name)
>
> If commented out line 15th, and run it again, the behavior is changed,
> only value is returned in the callback rather than expected char_value.
>