diff --git a/app-proto/src/assembly.rs b/app-proto/src/assembly.rs
index e8a8dc0..20b893d 100644
--- a/app-proto/src/assembly.rs
+++ b/app-proto/src/assembly.rs
@@ -120,6 +120,19 @@ pub struct Regulator {
     pub set_point_spec: Signal<String>
 }
 
+impl Regulator {
+    pub fn try_specify_set_point(&self, spec: String) -> bool {
+        match spec.parse::<f64>() {
+            Err(_) if !spec.is_empty() => false,
+            set_pt => {
+                self.set_point.set(set_pt.ok());
+                self.set_point_spec.set(spec);
+                true
+            }
+        }
+    }
+}
+
 // the velocity is expressed in uniform coordinates
 pub struct ElementMotion<'a> {
     pub key: ElementKey,
diff --git a/app-proto/src/outline.rs b/app-proto/src/outline.rs
index b0347f6..a48377b 100644
--- a/app-proto/src/outline.rs
+++ b/app-proto/src/outline.rs
@@ -50,17 +50,9 @@ fn RegulatorInput(regulator: Regulator) -> View {
             },
             placeholder=regulator.measurement.with(|result| result.to_string()),
             bind:value=value,
-            on:change=move |_| {
-                let value_val = value.get_clone_untracked();
-                match value_val.parse::<f64>() {
-                    Err(_) if !value_val.is_empty() => valid.set(false),
-                    set_pt => batch(|| {
-                        regulator.set_point.set(set_pt.ok());
-                        regulator.set_point_spec.set(value_val);
-                        valid.set(true);
-                    })
-                };
-            },
+            on:change=move |_| valid.set(
+                regulator.try_specify_set_point(value.get_clone_untracked())
+            ),
             on:keydown={
                 move |event: KeyboardEvent| {
                     match event.key().as_str() {