diff --git a/api/src/engine/connectors/exareme/transformations.ts b/api/src/engine/connectors/exareme/transformations.ts
index b124790ce8d25fe226df4d68d489b72256b611ea..e708954fe9284cc185dd2ea33c06858ba22f1deb 100644
--- a/api/src/engine/connectors/exareme/transformations.ts
+++ b/api/src/engine/connectors/exareme/transformations.ts
@@ -52,7 +52,7 @@ export const transformToExperiment = jsonata(`
                 algorithm.parameters[$not(name in $params)].({
                     "name": name,
                     "label": label,
-                    "value": value
+                    "value": $split(value, ',')
                 })
         }
     }
diff --git a/api/src/schema.gql b/api/src/schema.gql
index b2c3ddb14a0cd1ade6d856616c0f56634915c969..cc8aaa3d271e15134ff597424c864db35081e988 100644
--- a/api/src/schema.gql
+++ b/api/src/schema.gql
@@ -86,9 +86,9 @@ type GroupsResult {
 
 type HeatMapResult {
   name: String!
+  xAxis: ChartAxis
+  yAxis: ChartAxis
   matrix: [[Float!]!]!
-  xAxis: ChartAxis!
-  yAxis: ChartAxis!
 }
 
 type LineChartResult {