PollQueue

pyrogue.PollQueue is the Root-owned scheduler that drives periodic reads for polled variables.

In most applications you do not instantiate it directly. It is created by pyrogue.Root and controlled through root-level APIs/variables such as PollEn and variable pollInterval.

What it does

At runtime, PollQueue:

tracks poll entries per memory block (not per variable)
schedules reads using a time-ordered heap
issues block read transactions with startTransaction(..., Read)
waits for completion via checkTransaction
wraps each poll batch in root.updateGroup() so updates are coalesced

Block-Level Scheduling Behavior

Polling is organized per block:

if multiple variables share a block, the block is polled at the minimum non-zero pollInterval among those variables
when intervals change, the corresponding block entry is updated/replaced
if no variables in a block have pollInterval > 0, that block is removed from the poll queue

Special case for variables without a hardware block:

for dependency-only variables (for example link variables without _block), interval updates are propagated to dependencies

Control and Lifecycle

Poll thread starts during pyrogue.Root.start().
Root.PollEn controls pause/unpause (enabled when True).
Poll thread exits during pyrogue.Root.stop().
pyrogue.Root.pollBlock() can temporarily block polling inside a context manager.

Usage Examples

Basic polling on a RemoteVariable

import pyrogue as pr

class MyDevice(pr.Device):
    def __init__(self, **kwargs):
        super().__init__(**kwargs)
        self.add(pr.RemoteVariable(
            name='AdcRaw',
            offset=0x100,
            bitSize=16,
            mode='RO',
            base=pr.UInt,
            pollInterval=1.0,  # poll every second
        ))

Runtime control from Root

# Enable/disable polling globally
root.PollEn.set(True)
root.PollEn.set(False)

# Change polling rate dynamically for one variable
root.MyDevice.AdcRaw.setPollInterval(0.2)

Temporarily block polling during a critical sequence

with root.pollBlock():
    # perform operations that should not race with background poll reads
    root.MyDevice.SomeControl.set(1)
    root.MyDevice.OtherControl.set(0)

PollQueue Class Documentation

See PollQueue for generated API details.