diff --git a/db/versions/11010-blackChrysanthemum/00-firstScript.sql b/db/versions/11010-blackChrysanthemum/00-firstScript.sql
index a0d10891c..c8dce54b2 100644
--- a/db/versions/11010-blackChrysanthemum/00-firstScript.sql
+++ b/db/versions/11010-blackChrysanthemum/00-firstScript.sql
@@ -15,3 +15,7 @@ ALTER TABLE vn.deviceProductionUser ADD IF NOT EXISTS simSerialNumber TEXT NULL;
 ALTER TABLE vn.deviceProductionConfig ADD IF NOT EXISTS maxDevicesPerUser INT UNSIGNED NULL;
 
 UPDATE vn.deviceProductionConfig SET maxDevicesPerUser=1 WHERE id=1;
+
+INSERT IGNORE INTO salix.ACL (model,property,accessType,permission,principalType,principalId)
+	VALUES ('Worker','getAvailablePda','READ','ALLOW','ROLE','hr');
+
diff --git a/loopback/locale/en.json b/loopback/locale/en.json
index ca76eae42..601a26f5b 100644
--- a/loopback/locale/en.json
+++ b/loopback/locale/en.json
@@ -223,7 +223,8 @@
 	"printerNotExists": "The printer does not exist",
 	"There are not picking tickets": "There are not picking tickets",
 	"ticketCommercial": "The ticket {{ ticket }} for the salesperson {{ salesMan }} is in preparation. (automatically generated message)",
-    "This password can only be changed by the user themselves": "This password can only be changed by the user themselves",
-    "They're not your subordinate": "They're not your subordinate",
-	"InvoiceIn is already booked": "InvoiceIn is already booked"
-}
+	"This password can only be changed by the user themselves": "This password can only be changed by the user themselves",
+	"They're not your subordinate": "They're not your subordinate",
+	"InvoiceIn is already booked": "InvoiceIn is already booked",
+	"This workCenter is already assigned to this agency": "This workCenter is already assigned to this agency"
+}
\ No newline at end of file
diff --git a/loopback/locale/es.json b/loopback/locale/es.json
index f1c57455e..c67f7ecd6 100644
--- a/loopback/locale/es.json
+++ b/loopback/locale/es.json
@@ -355,6 +355,7 @@
 	"No results found": "No se han encontrado resultados",
 	"InvoiceIn is already booked": "La factura recibida está contabilizada",
 	"This workCenter is already assigned to this agency": "Este centro de trabajo ya está asignado a esta agencia",
-    "Select ticket or client": "Elija un ticket o un client",
-	"It was not able to create the invoice": "No se pudo crear la factura"
-}
+	"Select ticket or client": "Elija un ticket o un client",
+	"It was not able to create the invoice": "No se pudo crear la factura",
+	"This PDA is already assigned to another user": "This PDA is already assigned to another user"
+}
\ No newline at end of file
diff --git a/modules/worker/back/methods/worker/getAvailablePda.js b/modules/worker/back/methods/worker/getAvailablePda.js
new file mode 100644
index 000000000..5c97e15e1
--- /dev/null
+++ b/modules/worker/back/methods/worker/getAvailablePda.js
@@ -0,0 +1,25 @@
+module.exports = Self => {
+    Self.remoteMethod('getAvailablePda', {
+        description: 'returns devices without user',
+        accessType: 'READ',
+        accepts: [],
+        returns: {
+            type: 'array',
+            root: true
+        },
+        http: {
+            path: `/getAvailablePda`,
+            verb: 'GET'
+        }
+    });
+    Self.getAvailablePda = async() => {
+        const models = Self.app.models;
+
+        return models.DeviceProduction.rawSql(
+            `SELECT d.*
+                FROM deviceProduction d
+                    LEFT JOIN deviceProductionUser du ON du.deviceProductionFk = d.id
+                WHERE du.deviceProductionFk IS NULL`
+        );
+    };
+};
diff --git a/modules/worker/back/methods/worker/specs/getAvailablePda.spec.js b/modules/worker/back/methods/worker/specs/getAvailablePda.spec.js
new file mode 100644
index 000000000..7649225f1
--- /dev/null
+++ b/modules/worker/back/methods/worker/specs/getAvailablePda.spec.js
@@ -0,0 +1,13 @@
+const models = require('vn-loopback/server/server').models;
+
+describe('worker getAvailablePda()', () => {
+    fit('should return a Pda that has no user assigned', async() => {
+        const [{id}] = await models.Worker.getAvailablePda();
+
+        const deviceProductionUser = await models.DeviceProductionUser.findOne({
+            where: {deviceProductionFk: id}
+        });
+
+        expect(!deviceProductionUser).toBeTruthy();
+    });
+});
diff --git a/modules/worker/back/models/device-production-user.js b/modules/worker/back/models/device-production-user.js
new file mode 100644
index 000000000..81af484d3
--- /dev/null
+++ b/modules/worker/back/models/device-production-user.js
@@ -0,0 +1,8 @@
+const UserError = require('vn-loopback/util/user-error');
+module.exports = Self => {
+    Self.rewriteDbError(function(err) {
+        if (err.code === 'ER_DUP_ENTRY')
+            return new UserError(`This PDA is already assigned to another user`);
+        return err;
+    });
+};
diff --git a/modules/worker/back/models/device-production-user.json b/modules/worker/back/models/device-production-user.json
index d63fe0148..37955ab76 100644
--- a/modules/worker/back/models/device-production-user.json
+++ b/modules/worker/back/models/device-production-user.json
@@ -34,9 +34,9 @@
     },
     "relations": {
         "deviceProduction": {
-            "type": "belongsTo",
+            "type": "hasOne",
             "model": "DeviceProduction",
-            "foreignKey": "deviceProductionFk"
+            "foreignKey": "id"
         },
         "user": {
             "type": "belongsTo",
diff --git a/modules/worker/back/models/device-production.json b/modules/worker/back/models/device-production.json
index f6e5105ad..91b05eb85 100644
--- a/modules/worker/back/models/device-production.json
+++ b/modules/worker/back/models/device-production.json
@@ -55,6 +55,11 @@
             "type": "belongsTo",
             "model": "DeviceProductionState",
             "foreignKey": "stateFk"
+        },
+        "deviceProductionUser": {
+            "type": "hasMany",
+            "model": "DeviceProductionUser",
+            "foreignKey": "deviceProductionFk"
         }
     }
 }
diff --git a/modules/worker/back/models/worker.js b/modules/worker/back/models/worker.js
index b475bf26e..7128f973c 100644
--- a/modules/worker/back/models/worker.js
+++ b/modules/worker/back/models/worker.js
@@ -20,6 +20,7 @@ module.exports = Self => {
     require('../methods/worker/search')(Self);
     require('../methods/worker/isAuthorized')(Self);
     require('../methods/worker/setPassword')(Self);
+    require('../methods/worker/getAvailablePda')(Self);
 
     Self.validatesUniquenessOf('locker', {
         message: 'This locker has already been assigned'