diff --git a/src/yadg/dgutils/dsutils.py b/src/yadg/dgutils/dsutils.py
index 70fab7ff..8bc3e8ee 100644
--- a/src/yadg/dgutils/dsutils.py
+++ b/src/yadg/dgutils/dsutils.py
@@ -12,11 +12,8 @@ def append_dicts(
     devs: dict[str, Any],
     data: dict[str, list[Any]],
     meta: dict[str, list[Any]],
-    fn: str = None,
     li: int = 0,
 ) -> None:
-    if "_fn" in meta and fn is not None:
-        meta["_fn"].append(str(fn))
     for k, v in vals.items():
         if k not in data:
             data[k] = [None if isinstance(v, str) else np.nan] * li
@@ -29,8 +26,7 @@ def append_dicts(
     for k in set(data) - set(vals):
         data[k].append(np.nan)
     for k in set(meta) - set(devs):
-        if k != "_fn":
-            meta[k].append(np.nan)
+        meta[k].append(np.nan)
 
 
 def dicts_to_dataset(
@@ -54,10 +50,19 @@ def dicts_to_dataset(
             k = key
         darrs[k] = xr.DataArray(data=val, dims=["uts"], attrs=attrs)
         if key in meta and darrs[k].dtype.kind in {"i", "u", "f", "c", "m", "M"}:
-            err = f"{k}_std_err"
+            err = f"{k.replace(' ', '_')}_uncertainty"
             darrs[k].attrs["ancillary_variables"] = err
-            attrs["standard_name"] = f"{k} standard_error"
-            darrs[err] = xr.DataArray(data=meta[key], dims=["uts"], attrs=attrs)
+            attrs["standard_name"] = f"{k!r} standard_error"
+            attrs["yadg_uncertainty_absolute"] = 1
+            attrs["yadg_uncertainty_distribution"] = "rectangular"
+            attrs["yadg_uncertainty_source"] = "sigfig"
+            setdev = set(meta[key])
+            if np.nan in setdev:
+                setdev.remove(np.nan)
+            if len(setdev) == 1:
+                darrs[err] = xr.DataArray(data=setdev.pop(), dims=[], attrs=attrs)
+            else:
+                darrs[err] = xr.DataArray(data=meta[key], dims=["uts"], attrs=attrs)
     if "uts" in data:
         coords = dict(uts=data.pop("uts"))
     else:
@@ -79,7 +84,15 @@ def merge_dicttrees(vals: dict, fvals: dict, mode: str) -> dict:
         return fvals
     for k in fvals.keys():
         try:
-            vals[k] = xr.concat([vals[k], fvals[k]], dim="uts", combine_attrs=mode)
+            # vals[k] = xr.concat([vals[k], fvals[k]], dim="uts", combine_attrs=mode)
+            vals[k] = xr.concat(
+                [vals[k], fvals[k]],
+                dim="uts",
+                data_vars="different",
+                compat="identical",
+                join="outer",
+                combine_attrs=mode,
+            )
         except xr.MergeError:
             raise RuntimeError(
                 "Merging metadata from multiple files has failed, as some of the "
diff --git a/src/yadg/extractors/basic/csv.py b/src/yadg/extractors/basic/csv.py
index 10d9e5d0..96264f43 100644
--- a/src/yadg/extractors/basic/csv.py
+++ b/src/yadg/extractors/basic/csv.py
@@ -46,7 +46,6 @@
 from pydantic import BaseModel
 from babel.numbers import parse_decimal
 from xarray import DataTree
-from uncertainties.core import str_to_number_with_uncert as tuple_fromstr
 from typing import Callable
 from pathlib import Path
 from yadg.extractors import get_extract_dispatch
@@ -108,9 +107,10 @@ def process_row(
         elif columns[ci] == "":
             continue
         try:
-            val, dev = tuple_fromstr(str(parse_decimal(columns[ci], locale=locale)))
-            vals[header] = val
-            devs[header] = dev
+            dec = parse_decimal(columns[ci], locale=locale)
+            exp = dec.as_tuple().exponent
+            vals[header] = float(dec)
+            devs[header] = 10**exp
         except ValueError:
             vals[header] = columns[ci]
 
@@ -165,7 +165,7 @@ def extract(
 
     # Process rows
     data_vals = {}
-    meta_vals = {"_fn": []}
+    meta_vals = {}
     for li, line in enumerate(lines[si:]):
         vals, devs = process_row(
             headers,
@@ -174,6 +174,6 @@ def extract(
             datecolumns,
             locale=locale,
         )
-        dgutils.append_dicts(vals, devs, data_vals, meta_vals, str(source), li)
+        dgutils.append_dicts(vals, devs, data_vals, meta_vals, li)
 
     return DataTree(dgutils.dicts_to_dataset(data_vals, meta_vals, units, fulldate))
diff --git a/src/yadg/extractors/drycal/common.py b/src/yadg/extractors/drycal/common.py
index 43d320a4..983302c0 100644
--- a/src/yadg/extractors/drycal/common.py
+++ b/src/yadg/extractors/drycal/common.py
@@ -70,10 +70,10 @@ def rtf(
 
     # Process rows
     data_vals = {}
-    meta_vals = {"_fn": []}
+    meta_vals = {}
     for pi, point in enumerate(data):
         vals, devs = process_row(headers[1:], point[1:], datefunc, datecolumns)
-        dgutils.append_dicts(vals, devs, data_vals, meta_vals, fn, pi)
+        dgutils.append_dicts(vals, devs, data_vals, meta_vals, pi)
 
     return dgutils.dicts_to_dataset(data_vals, meta_vals, units, False)
 
@@ -118,10 +118,10 @@ def sep(
 
     # Process rows
     data_vals = {}
-    meta_vals = {"_fn": []}
+    meta_vals = {}
     for pi, point in enumerate(data):
         vals, devs = process_row(headers[1:], point[1:], datefunc, datecolumns)
-        dgutils.append_dicts(vals, devs, data_vals, meta_vals, fn, pi)
+        dgutils.append_dicts(vals, devs, data_vals, meta_vals, pi)
 
     return dgutils.dicts_to_dataset(data_vals, meta_vals, units, False)
 
diff --git a/src/yadg/extractors/eclab/mpr.py b/src/yadg/extractors/eclab/mpr.py
index 9c50b6b1..c9e84ee4 100644
--- a/src/yadg/extractors/eclab/mpr.py
+++ b/src/yadg/extractors/eclab/mpr.py
@@ -206,6 +206,8 @@
     extdev_dtypes,
 )
 
+from .mpt import dicts_to_dataset
+
 logger = logging.getLogger(__name__)
 extract = get_extract_dispatch()
 
@@ -478,7 +480,7 @@ def process_data(
     if warn_Ns:
         logger.warning("Ns found in data exceeds Ns in header, using last defined Ns.")
 
-    ds = dgutils.dicts_to_dataset(allvals, allmeta, units, fulldate=False)
+    ds = dicts_to_dataset(allvals, allmeta, units, fulldate=False)
     return ds
 
 
diff --git a/src/yadg/extractors/eclab/mpt.py b/src/yadg/extractors/eclab/mpt.py
index 7fc46b37..faa9772a 100644
--- a/src/yadg/extractors/eclab/mpt.py
+++ b/src/yadg/extractors/eclab/mpt.py
@@ -55,7 +55,7 @@
 import logging
 from typing import Any
 from babel.numbers import parse_decimal
-from xarray import DataTree
+from xarray import DataTree, Dataset, DataArray
 from yadg import dgutils
 from .techniques import get_devs, param_from_key, split_control
 from .mpt_columns import column_units
@@ -66,6 +66,42 @@
 extract = get_extract_dispatch()
 
 
+def dicts_to_dataset(
+    data: dict[str, list[Any]],
+    meta: dict[str, list[Any]],
+    units: dict[str, str] = dict(),
+    fulldate: bool = True,
+) -> Dataset:
+    darrs = {}
+    for key, val in data.items():
+        attrs = {}
+        u = units.get(key, None)
+        if u is not None:
+            attrs["units"] = u
+        if key == "uts":
+            continue
+        if "/" in key:
+            logger.warning(f"Replacing '/' for '_' in column {key!r}.")
+            k = key.replace("/", "_")
+        else:
+            k = key
+        darrs[k] = DataArray(data=val, dims=["uts"], attrs=attrs)
+        if key in meta and darrs[k].dtype.kind in {"i", "u", "f", "c", "m", "M"}:
+            err = f"{k}_std_err"
+            darrs[k].attrs["ancillary_variables"] = err
+            attrs["standard_name"] = f"{k} standard_error"
+            darrs[err] = DataArray(data=meta[key], dims=["uts"], attrs=attrs)
+    if "uts" in data:
+        coords = dict(uts=data.pop("uts"))
+    else:
+        coords = dict()
+    if fulldate:
+        attrs = dict()
+    else:
+        attrs = dict(fulldate=False)
+    return Dataset(data_vars=darrs, coords=coords, attrs=attrs)
+
+
 def process_settings(lines: list[str]) -> dict[str, str]:
     settings = {}
     comments = []
@@ -303,7 +339,7 @@ def process_data(
     if warn_I_range:
         logger.warning("I Range could not be understood, defaulting to 1 A.")
 
-    ds = dgutils.dicts_to_dataset(allvals, allmeta, units, fulldate=False)
+    ds = dicts_to_dataset(allvals, allmeta, units, fulldate=False)
     return ds
 
 
diff --git a/src/yadg/extractors/fhimcpt/csv.py b/src/yadg/extractors/fhimcpt/csv.py
index cded2093..7b6c877d 100644
--- a/src/yadg/extractors/fhimcpt/csv.py
+++ b/src/yadg/extractors/fhimcpt/csv.py
@@ -98,6 +98,6 @@ def extract_from_path(
             datefunc,
             datecolumns,
         )
-        dgutils.append_dicts(vals, devs, data_vals, meta_vals, str(source), li)
+        dgutils.append_dicts(vals, devs, data_vals, meta_vals, li)
 
     return DataTree(dgutils.dicts_to_dataset(data_vals, meta_vals, units, fulldate))
diff --git a/src/yadg/extractors/tomato/json.py b/src/yadg/extractors/tomato/json.py
index f7039ab8..5abd0ef2 100644
--- a/src/yadg/extractors/tomato/json.py
+++ b/src/yadg/extractors/tomato/json.py
@@ -183,7 +183,7 @@ def dummy_tomato_json(fn: Path, jsdata: dict) -> DataTree:
         for k, v in vals.items():
             if k not in {"time", "address", "channel"}:
                 devs[k] = 0.0
-        dgutils.append_dicts(vals, devs, data_vals, meta_vals, str(fn), vi)
+        dgutils.append_dicts(vals, devs, data_vals, meta_vals, vi)
     return DataTree(dgutils.dicts_to_dataset(data_vals, meta_vals, fulldate=False))
 
 
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