diff --git a/AutoCAD/IO/IO.xlsx b/AutoCAD/IO/IO.xlsx
deleted file mode 100644
index 6c87dd5..0000000
Binary files a/AutoCAD/IO/IO.xlsx and /dev/null differ
diff --git a/AutoCAD/IO/MCM_IO.xlsx b/AutoCAD/IO/MCM_IO.xlsx
index a7eefa4..633e5ba 100644
Binary files a/AutoCAD/IO/MCM_IO.xlsx and b/AutoCAD/IO/MCM_IO.xlsx differ
diff --git a/AutoCAD/IO/__pycache__/build_io_table.cpython-314.pyc b/AutoCAD/IO/__pycache__/build_io_table.cpython-314.pyc
new file mode 100644
index 0000000..785df07
Binary files /dev/null and b/AutoCAD/IO/__pycache__/build_io_table.cpython-314.pyc differ
diff --git a/AutoCAD/IO/build_io_table.py b/AutoCAD/IO/build_io_table.py
index fd5c56d..f4a1abd 100644
--- a/AutoCAD/IO/build_io_table.py
+++ b/AutoCAD/IO/build_io_table.py
@@ -61,13 +61,28 @@ def family_keys(dev: str):
             seen.add(k); out.append(k)
     return out
 
-def fallback_desc(dev: str) -> str:
+def bcn_desc_s_stack(dev: str, all_devices: set) -> str | None:
+    """Returns IO LINK description for S-prefixed BCNs, or None if not applicable."""
+    import re as _re
+    d = dev.upper()
+    m = _re.match(r"(S\d+)_BCN\d*", d)
+    if not m:
+        return None
+    base = m.group(1)
+    jr_pattern = _re.compile(rf"{_re.escape(base)}_JR\d")
+    has_jr = any(jr_pattern.search(dv) for dv in all_devices)
+    if has_jr:
+        return "IO LINK 3 STACK G/A/B BEACON"
+    return "IO LINK 2 STACK G/B BEACON"
+
+def fallback_desc(dev: str, all_devices: set | None = None) -> str:
     import re as _re
     d = dev.upper()
     if d == "SPARE": return ""
     if "VFD" in d and ("DISC" in d or "DSIC" in d): return "DISCONNECT AUX"
     if _re.search(r"_TPE\d+|^TPE\d+", d): return "TRACKING PHOTOEYE"
     if _re.search(r"_JPE\d+|^JPE\d+", d): return "JAM PHOTOEYE"
+    if _re.search(r"S\d+_PE\d*|_PE\d+|^PE\d+", d): return "CHUTE DISABLE PHOTOEYE"
     if _re.search(r"_EPC\d+|^EPC\d+", d): return "E-STOP PULLCORD"
     if "ENSH" in d: return "SHAFT ENCODER"
     if "ENW" in d: return "WHEEL ENCODER"
@@ -78,6 +93,9 @@ def fallback_desc(dev: str) -> str:
     if any(x in d for x in ["_SOL","_SOV","_SV","_SOLV"]): return "SOLENOID VALVE"
     if _re.search(r"_FIOH\d+|^FIOH\d+", d): return "I/O LINK HUB"
     if "BCN" in d:
+        s_bcn_desc = bcn_desc_s_stack(d, all_devices or set())
+        if s_bcn_desc:
+            return s_bcn_desc
         if d.endswith("_A"): return "AMBER BEACON LIGHT"
         if d.endswith("_R"): return "RED BEACON LIGHT"
         if d.endswith("_G"): return "GREEN BEACON LIGHT"
@@ -97,13 +115,13 @@ def fallback_desc(dev: str) -> str:
     if d.startswith("PDP") and "_PWM" in d: return "PHASE MONITOR"
     return "DEVICE"
 
-def desc_for(dev: str, canon: dict) -> str:
+def desc_for(dev: str, canon: dict, all_devices: set | None = None) -> str:
     s = str(dev).strip().upper()
     if not s: return ""
     if s in canon: return canon[s]
     for k in family_keys(s):
         if k in canon: return canon[k]
-    return fallback_desc(s)
+    return fallback_desc(s, all_devices)
 
 def choose_order(controller_name: str, available_columns):
     s = str(controller_name).upper()
@@ -145,6 +163,17 @@ def main():
 
     canon_map = load_canon([Path(p) for p in args.canon])
 
+    all_devices = set()
+    for _, r in df.iterrows():
+        ctrl = str(r.get("P_TAG1", "")).strip()
+        if not ctrl:
+            continue
+        order = choose_order(ctrl, sig_cols_available)
+        for sig in order:
+            val = r.get(sig)
+            if pd.notna(val) and str(val).strip():
+                all_devices.add(str(val).strip().upper())
+
     rows = []
     for _, r in df.iterrows():
         ctrl = str(r.get("P_TAG1","")).strip()
@@ -157,7 +186,7 @@ def main():
             if dev == "":
                 dev = "SPARE"
             addr = f"{ctrl}_{sig}"
-            desc = "" if dev.upper()=="SPARE" else desc_for(dev, canon_map)
+            desc = "" if dev.upper()=="SPARE" else desc_for(dev, canon_map, all_devices)
             dU = dev.upper()
             if re.search(r'_ESTOP1$', dU): desc = "ESTOP OK"
             elif re.search(r'_SS\d+_SPB_LT$', dU): desc = "SS STATION START PUSHBUTTON LIGHT"
@@ -169,6 +198,7 @@ def main():
             elif re.search(r'_JR\d+_PB$', dU): desc = "JAM RESET PUSHBUTTON"
             elif re.search(r'_EN\d*_PB_LT$', dU): desc = "ENABLE PUSHBUTTON LIGHT"
             elif re.search(r'_EN\d*_PB$', dU): desc = "ENABLE PUSHBUTTON"
+            elif re.search(r'_PR\d*_PB$', dU): desc = "PACKAGE RELEASE PUSHBUTTON"
             rows.append({
                 "Controller name": ctrl,
                 "Signal type": sig,