diff --git a/tools/autotest/test_isone.glm b/tools/autotest/test_isone.glm
index 20fb36441..44f01ba43 100644
--- a/tools/autotest/test_isone.glm
+++ b/tools/autotest/test_isone.glm
@@ -1,4 +1,4 @@
-#python -m isone -d=smd/ME -s=2020-03-01 -e=2020-03-01 -c=test_isone.csv -g=test_isone_opt.glm
+#python -m isone -D=smd/ME -s=2020-03-01 -e=2020-03-01 -c=test_isone.csv -g=test_isone_opt.glm
 module tape
 {
     csv_header_type NAME;
diff --git a/tools/isone.py b/tools/isone.py
index f7b8b71a8..e93f8c44c 100644
--- a/tools/isone.py
+++ b/tools/isone.py
@@ -1,9 +1,25 @@
+# Syntax: isone [OPTIONS ...]
 """ISO New England data access module
 
-Syntax: gridlabd isone OPTIONS ...
+Syntax
+------
 
-Options:
-    -d|--dataset=DATASET/SUBSET     Download data from the specified dataset
+Shell:
+
+~~~
+gridlabd isone [OPTIONS ...]
+~~~
+
+GLM:
+
+~~~
+#python -m isone [OPTIONS ...]
+~~~
+
+Options
+-------
+    -d|-debug                       Enable traceback output on exceptions
+    -D|--dataset=DATASET/SUBSET     Download data from the specified dataset
                                     (and subset, default is `smd/ISO NE CA`)
     -c|--csv=FILENAME               Save CSV data to the specified file
                                     (default is /dev/stdout)
@@ -14,17 +30,37 @@
     -f|--freshen                    Freshen the data cache
     -g|--glm=FILENAME               Save GLM data to the specified file
                                     (default is /dev/null)
+    -h|--help|help                  Output the help documentation
     -l|--list                       Output a list of available sheets in dataset
     -N|--NAME=OBJECTNAME            Specify the GLM object name (default is
                                     `isone`)
+    -q|--quiet                      Suppress error output messages
     -s|--start=YEAR|STARTDATE       Download data starting on the specified
                                     year or date (last month by default)
+    -v|--verbose                    Enable verbose output
     -y|--year[=YEAR]                Download data for the specified year
                                     (current year by default)
 
 Currently the only supported dataset is `smd`. The valid subsets depend on the
 dataset and year. See https://www.iso-ne.com/isoexpress/web/reports/load-and-demand/-/tree/zone-info
 for more information.
+
+Example
+-------
+
+The following generates the wholesale market data New Hampshire for May 2023:
+
+~~~
+sh$ gridlabd isone -D=smd/NH -f -s=2023-05-01 -e=2023-06-01
+timestamp,DA_Demand,RT_Demand,DA_LMP,DA_EC,DA_CC,DA_MLC,RT_LMP,RT_EC,RT_CC,RT_MLC,Dry_Bulb,Dew_Point
+2023-05-01 00:00:00,801.30,924.94,24.63,24.64,-0.05,0.04,18.96,18.75,0.18,0.03,53,51
+2023-05-01 01:00:00,807.90,899.31,20.61,20.59,-0.03,0.05,18.88,18.70,0.18,0.00,54,53
+2023-05-01 02:00:00,765.20,885.84,20.56,20.57,-0.03,0.02,18.12,17.73,0.41,-0.02,54,53
+...
+2023-06-01 21:00:00,1753.00,1594.43,58.33,57.55,0.00,0.78,41.90,41.65,0.00,0.25,75,61
+2023-06-01 22:00:00,1495.20,1425.32,50.57,50.31,0.00,0.26,35.95,35.82,0.00,0.13,77,59
+2023-06-01 23:00:00,1269.60,1283.86,53.36,52.86,0.00,0.50,36.52,36.40,0.00,0.12,77,59
+~~~
 """
 
 import sys, os
@@ -34,7 +70,7 @@
 import traceback
 
 EXECNAME = os.path.splitext(os.path.basename(sys.argv[0]))[0]
-DATASET = "smd"
+DATASET = "smd/ISO NE CA"
 CSVFILE = "/dev/stdout"
 GLMFILE = None
 CLASSNAME = "isone"
@@ -55,7 +91,12 @@
 E_INVALID = 2
 E_FAILED = 3
 
+class IsoneException(Exception):
+    pass
+
 def error(msg,code=None):
+    if DEBUG:
+        raise IsoneException(msg)
     if not QUIET:
         print(f"ERROR [{EXECNAME}]: {msg}",flush=True,file=sys.stderr)
     if not code is None:
@@ -79,6 +120,9 @@ def get_year(year=None,dataset=None):
         dataset = DATASET
         verbose(f"setting to default dataset '{dataset}'")
     specs = dataset.split("/")
+    if len(specs) != 2:
+        error(f"dataset {dataset} is not valid",E_INVALID)
+
     cachefile = os.path.join(CACHEDIR,f"{specs[0]}_{year}.xlsx")
     if FRESHEN or not os.path.exists(cachefile):
         verbose(f"creating cache directory '{CACHEDIR}'")
@@ -95,12 +139,8 @@ def get_year(year=None,dataset=None):
                 error(f"unable to download data from '{url}' (HTTP code {req.status_code})",E_FAILED)
         except Exception as err:
             error(f"unable to get data from '{url}' ({err})",E_FAILED)
-    if len(specs) > 1:
-        verbose(f"loading '{specs[1]}' from '{cachefile}'")
-        return pandas.read_excel(cachefile,sheet_name=specs[1],index_col=[0,1],parse_dates=[0])
-    else:
-        verbose(f"loading data from '{cachefile}'")
-        return pandas.read_excel(cachefile,sheet_name=None)
+    verbose(f"loading '{specs[1]}' from '{cachefile}'")
+    return pandas.read_excel(cachefile,sheet_name=specs[1],index_col=[0,1],parse_dates=[0])
 
 def get_data(startdate=None,stopdate=None,dataset=None):
     """Get data from a date range
@@ -110,10 +150,10 @@ def get_data(startdate=None,stopdate=None,dataset=None):
     :return: pandas.DataFrame - the requested data
     """
     if startdate == None:
-        startdate = datetime.datetime(year=datetime.datetime.now().year)
+        startdate = datetime.datetime(year=datetime.datetime.now().year,month=1,day=1)
     else:
         startdate = datetime.datetime.strptime(startdate,DATEFORMAT)
-    if startdate == None:
+    if stopdate == None:
         stopdate = datetime.datetime.now()
     else:
         stopdate = datetime.datetime.strptime(stopdate,DATEFORMAT)
@@ -159,12 +199,12 @@ def fix_timestamps(df):
             VERBOSE = True
         elif token in ["-q","--quiet"]:
             QUIET = True
-        elif token in ["--debug"]:
+        elif token in ["-d","--debug"]:
             DEBUG = True
 
-        # -d|--dataset=DATASET/SUBSET     Download data from the specified dataset
+        # -D|--dataset=DATASET/SUBSET     Download data from the specified dataset
         #                                 (and subset, default is `smd/ISO NE CA`)
-        elif token in ["-d","--dataset"]:
+        elif token in ["-D","--dataset"]:
             if value:
                 DATASET = value 
             else: