Hello, Sidekick System!¶

A simple example showing how to print out some variables from your sidekick system, and set some as well. Uses the "pyepics" code.

Run this from a laptop on your same network as the sidekick devices.

Start this Python kernel after joining the proper network.

References:¶

1. PyEpics
2. PyEpics PV Class

In [1]:

import epics

import epics

Read some values!¶

In [2]:

epics.caget("LEDS:info")

epics.caget("LEDS:info")

Out[2]:

'DolphinDAQ,Arduino LEDs,#00,v0.1'

In [3]:

epics.caget("SHUTTER:info")

epics.caget("SHUTTER:info")

Out[3]:

'DolphinDAQ,Arduino Shutter,#00,v0.1'

In [9]:

epics.caget("PULSEGEN:info")

epics.caget("PULSEGEN:info")

Out[9]:

'DolphinDAQ,Arduino PulseGen,#00,v0.2'

In [10]:

epics.caget("LEDS:CH0:dur") # Read pulse duration of LED#0

epics.caget("LEDS:CH0:dur") # Read pulse duration of LED#0

Out[10]:

200000.0

You should get "200000.0" above. If you got "None" instead, you're not establishing a proper connection to the EPICS sidekick system. Check your network connection and try again!

Examine fields other than just the value¶

Examining individual fields¶

In [6]:

print("PV Name: ", epics.caget("PULSEGEN:CH2:delay.NAME"))
print("PV Value: ", epics.caget("PULSEGEN:CH2:delay.VAL"))
print("PV Description: ", epics.caget("PULSEGEN:CH2:delay.DESC"))
print("PV Units: ", epics.caget("PULSEGEN:CH2:delay.EGU"))

print("PV Name: ", epics.caget("PULSEGEN:CH2:delay.NAME")) print("PV Value: ", epics.caget("PULSEGEN:CH2:delay.VAL")) print("PV Description: ", epics.caget("PULSEGEN:CH2:delay.DESC")) print("PV Units: ", epics.caget("PULSEGEN:CH2:delay.EGU"))

PV Name:  PULSEGEN:CH2:delay
PV Value:  2000.0
PV Description:  Set pulse delay time
PV Units:  micros

In [7]:

channel = "SHUTTER:dur"
for field, label in zip(["NAME", "VAL", "DESC", "EGU"], ["Name", "Value", "Description", "Units"]):
    print("PV " + label + ": ", epics.caget(channel + "." + field))

channel = "SHUTTER:dur" for field, label in zip(["NAME", "VAL", "DESC", "EGU"], ["Name", "Value", "Description", "Units"]): print("PV " + label + ": ", epics.caget(channel + "." + field))

PV Name:  SHUTTER:dur
PV Value:  500000.0
PV Description:  Set shutter-open duration (output)
PV Units:  micros

Examining all info about a PV¶

Or even more efficiently, we could just use the "cainfo" method!

In [8]:

epics.cainfo("PULSEGEN:CH2:delay")

epics.cainfo("PULSEGEN:CH2:delay")

== PULSEGEN:CH2:delay  (time_double) ==
   value      = 2000
   char_value = '2000'
   count      = 1
   nelm       = 1
   type       = time_double
   units      = micros
   precision  = 0
   host       = epics1.epics-net:5064
   access     = read/write
   status     = 0
   char_status= NO_ALARM
   severity   = 0
   char_severity       = NO_ALARM
   timestamp  = 631152000.000 (1989-12-31 16:00:00.00000)
   posixseconds        = 631152000.0
   nanoseconds= 0
   upper_ctrl_limit    = 4294967295.0
   lower_ctrl_limit    = 0.0
   upper_disp_limit    = 0.0
   lower_disp_limit    = 0.0
   upper_alarm_limit   = 0.0
   lower_alarm_limit   = 0.0
   upper_warning_limit = 0.0
   lower_warning_limit = 0.0
   PV is internally monitored, with 0 user-defined callbacks:
=============================

Set some values!¶

In [9]:

epics.caput("LEDS:CH0:brig", 0) # Suppress output from LED #0 by setting brightness to "0" (out of 255)

epics.caput("LEDS:CH0:brig", 0) # Suppress output from LED #0 by setting brightness to "0" (out of 255)

Out[9]:

1

In [10]:

epics.caput("LEDS:CH3:brig", 255) # Maximize brightness from LED #3 by setting brightness to "255" (out of 255)

epics.caput("LEDS:CH3:brig", 255) # Maximize brightness from LED #3 by setting brightness to "255" (out of 255)

Out[10]:

1

In [11]:

epics.caput("LEDS:CH5:dur", 500e3) # Maximize brightness from LED #3 by setting brightness to "255" (out of 255)

epics.caput("LEDS:CH5:dur", 500e3) # Maximize brightness from LED #3 by setting brightness to "255" (out of 255)

Out[11]:

1

Object-Oriented Approach¶

The above uses procedural methods like "caget", "caput", and "cainfo". There is also an object-oriented approach in pyepics that can be quite powerful.

In [12]:

from epics import PV

from epics import PV

In [13]:

mypv = PV('LEDS:CH4:brig.VAL')
mypv.get() # Get brightness of LED #4

mypv = PV('LEDS:CH4:brig.VAL') mypv.get() # Get brightness of LED #4

Out[13]:

200

In [14]:

mypv.put(255) # Maximize brightness from LED #4 by setting brightness to "255" (out of 255)

mypv.put(255) # Maximize brightness from LED #4 by setting brightness to "255" (out of 255)

Out[14]:

1