From ba3eab207456464e59a9e20a8d6cb4897012b125 Mon Sep 17 00:00:00 2001
From: Sven Augustin <sven.augustin@psi.ch>
Date: Wed, 15 Sep 2021 22:32:06 +0200
Subject: [PATCH] read, use or compare reference undulator currently used by
 the machine

---
 devices/undulator.py | 54 ++++++++++++++++++++++++++++++++++++++------
 1 file changed, 47 insertions(+), 7 deletions(-)

diff --git a/devices/undulator.py b/devices/undulator.py
index f903411..5cef4b8 100644
--- a/devices/undulator.py
+++ b/devices/undulator.py
@@ -4,30 +4,51 @@ from epics import PV
 
 from logzero import logger as log
 
-from slic.core.adjustable import Adjustable
-from slic.core.adjustable import PVAdjustable
+from slic.core.adjustable import Adjustable, PVAdjustable, PVEnumAdjustable
 from slic.core.scanner.scanbackend import wait_for_all #, stop_all
 
 
 UND_NAME_FMT = "SATUN{:02}-UIND030"
 N_UND_CHIC = 14
 
+N_UNDS = list(range(6, 22+1))
+N_UNDS.remove(N_UND_CHIC)
+
+
 
 class Undulators(Adjustable):
+    """
+    for n_und_ref=None (default), the reference undulator currently used by the machine will be used
+    """
 
-    def __init__(self, n_unds, n_und_ref, chic_fudge_offset=0, adjust_chic=True, scaled=True, ID="ATHOS_UNDULATORS", name="Athos Undulators", units="eV"):
+    def __init__(self, n_unds=N_UNDS, n_und_ref=None, chic_fudge_offset=0, adjust_chic=True, scaled=True, ID="ATHOS_UNDULATORS", name="Athos Undulators", units="eV"):
         super().__init__(ID, name=name, units=units)
 
-        self.n_unds = n_unds = list(n_unds)
-        self.n_und_ref = n_und_ref
 
-        if n_und_ref not in n_unds:
-            raise ValueError(f"the reference undulator ({n_und_ref}) is not in the list of active undulators: {n_unds}")
+        machine_n_und_ref = get_machine_n_und_ref()
+
+        if n_und_ref is None:
+            if machine_n_und_ref is None:
+                raise ValueError(f"could not read reference undulator currently used by the machine, please specify n_und_ref")
+            n_und_ref = machine_n_und_ref
+
+        if n_und_ref != machine_n_und_ref:
+            log.warning(f"the chosen reference undulator ({n_und_ref}) is not the reference undulator currently used by the machine ({machine_n_und_ref})")
+
+
+        n_unds = list(n_unds)
 
         if N_UND_CHIC in n_unds:
             log.warning(f"the CHIC ({N_UND_CHIC}) is in the list of active undulators: {n_unds}, and will be ignored/removed")
             n_unds.remove(N_UND_CHIC)
 
+        if n_und_ref not in n_unds:
+            raise ValueError(f"the reference undulator ({n_und_ref}) is not in the list of active undulators: {n_unds}")
+
+
+        self.n_unds = n_unds
+        self.n_und_ref = n_und_ref
+
         self.und_names = und_names = [UND_NAME_FMT.format(n) for n in n_unds]
         self.und_name_cal = und_name_cal = UND_NAME_FMT.format(n_und_ref)
 
@@ -43,6 +64,7 @@ class Undulators(Adjustable):
         self.scale = ScalerEK(a)
 
 
+
     def set_target_value(self, value, hold=False):
         k = self.convert.K(value)
         if np.isnan(k):
@@ -200,3 +222,21 @@ class CHIC(PVAdjustable):
 
 
 
+
+
+def get_machine_n_und_ref():
+    res = PVEnumAdjustable("SATUN:REF-UND").get()
+    if not res.startswith("SATUN"):
+        return None
+    n = len("SATUN")
+    res = res[n:]
+    try:
+        res = int(res)
+    except ValueError:
+        return None
+    return res
+
+
+
+
+