Merge pull request #1285 from DiamondLightSource/fix_occasional_panda…

…_error

Fix occasional panda error

src/hyperion/device_setup_plans/setup_panda.py

@@ -140,12 +140,18 @@ def setup_panda_for_flyscan(
 
     # Home the PandA X encoder using current motor position
     yield from bps.abs_set(
-        panda.inenc[1].setp, initial_x * MM_TO_ENCODER_COUNTS, wait=True  # type: ignore
+        panda.inenc[1].setp,  # type: ignore
+        initial_x * MM_TO_ENCODER_COUNTS,
+        wait=True,
     )
 
     LOGGER.info(f"Setting PandA clock to period {time_between_x_steps_ms}")
 
-    yield from bps.abs_set(panda.clock[1].period, time_between_x_steps_ms, group="panda-config")  # type: ignore
+    yield from bps.abs_set(
+        panda.clock[1].period,  # type: ignore
+        time_between_x_steps_ms,
+        group="panda-config",
+    )
 
     yield from bps.abs_set(
         panda.pulse[1].width, DETECTOR_TRIGGER_WIDTH, group="panda-config"
@@ -159,19 +165,24 @@ def setup_panda_for_flyscan(
 
     yield from bps.abs_set(panda.seq[1].table, table, group="panda-config")
 
-    # Wait here since we need PCAP to be enabled before armed
-    yield from bps.abs_set(panda.pcap.enable, Enabled.ENABLED.value, wait=True)  # type: ignore
-
-    yield from arm_panda_for_gridscan(panda, group="panda-config")
+    yield from bps.abs_set(
+        panda.pcap.enable,  # type: ignore
+        Enabled.ENABLED.value,
+        group="panda-config",
+    )
 
+    # Values need to be set before blocks are enabled, so wait here
     yield from bps.wait(group="panda-config", timeout=GENERAL_TIMEOUT)
 
+    yield from arm_panda_for_gridscan(panda)
+
 
 def arm_panda_for_gridscan(panda: PandA, group="arm_panda_gridscan"):
     yield from bps.abs_set(panda.seq[1].enable, Enabled.ENABLED.value, group=group)  # type: ignore
     yield from bps.abs_set(panda.pulse[1].enable, Enabled.ENABLED.value, group=group)  # type: ignore
     yield from bps.abs_set(panda.counter[1].enable, Enabled.ENABLED.value, group=group)  # type: ignore
     yield from bps.abs_set(panda.pcap.arm, PcapArm.ARMED.value, group=group)  # type: ignore
+    yield from bps.wait(group=group, timeout=GENERAL_TIMEOUT)
 
 
 def disarm_panda_for_gridscan(panda, group="disarm_panda_gridscan") -> MsgGenerator:

tests/unit_tests/device_setup_plans/test_setup_panda.py

@@ -2,6 +2,8 @@
 
 import numpy as np
 import pytest
+from bluesky.plan_stubs import null
+from bluesky.run_engine import RunEngine
 from dodal.devices.panda_fast_grid_scan import PandAGridScanParams
 from ophyd_async.panda import SeqTrigger
 
@@ -159,6 +161,42 @@ def test_setup_panda_correctly_configures_table(
     np.testing.assert_array_equal(table["outa2"], np.array([0, 1, 0, 0, 1, 0]))
 
 
+def test_wait_between_setting_table_and_arming_panda(RE: RunEngine):
+    bps_wait_done = False
+
+    def handle_wait(*args, **kwargs):
+        nonlocal bps_wait_done
+        bps_wait_done = True
+        yield from null()
+
+    def assert_set_table_has_been_waited_on(*args, **kwargs):
+        assert bps_wait_done
+        yield from null()
+
+    with patch(
+        "hyperion.device_setup_plans.setup_panda.arm_panda_for_gridscan",
+        MagicMock(side_effect=assert_set_table_has_been_waited_on),
+    ), patch(
+        "hyperion.device_setup_plans.setup_panda.bps.wait",
+        MagicMock(side_effect=handle_wait),
+    ), patch(
+        "hyperion.device_setup_plans.setup_panda.load_device"
+    ), patch(
+        "hyperion.device_setup_plans.setup_panda.bps.abs_set"
+    ):
+        RE(
+            setup_panda_for_flyscan(
+                MagicMock(),
+                "path",
+                PandAGridScanParams(),
+                1,
+                1,
+                1,
+                get_smargon_speed(0.1, 1),
+            )
+        )
+
+
 # It also would be useful to have some system tests which check that (at least)
 # all the blocks which were enabled on setup are also disabled on tidyup
 def test_disarm_panda_disables_correct_blocks():