# Bad\_NotWritable: The access level does not allow writing to the Node **URL:** \ **Category:** Ignition\ **Created:** [April 28, 2022, 4:17pm UTC](https://forum.inductiveautomation.com/t/bad-notwritable-the-access-level-does-not-allow-writing-to-the-node/59005 "2022-04-28T16:17:23Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![Simon.de.Kraa](https://avatars.discourse-cdn.com/v4/letter/s/82dd89/32.png) [@Simon.de.Kraa](https://forum.inductiveautomation.com/u/Simon.de.Kraa)\ **Post date:** [April 28, 2022, 4:17pm UTC](https://forum.inductiveautomation.com/t/bad-notwritable-the-access-level-does-not-allow-writing-to-the-node/59005/1 "2022-04-28T16:17:23Z")
Hello, When I try to write data to a tag I get the following error message. `Bad_NotWritable: The access level does not allow writing to the Node.` I have created a few API endpoints using Web Dev as follows: **createTags - doPost** ```auto basePath = request['data']['basePath'] tags = request['data']['tags'] collisionPolicy = request['data']['collisionPolicy'] result = system.tag.configure(basePath, tags, collisionPolicy) return {'json': result} ``` **tag - doPost** ```auto paths = request['data']['paths'] values = request['data']['values'] result = system.tag.writeBlocking(paths, values) return {'json': result} ``` I create an additional tag in the Tag Provider `[Sample_Tags]` by calling `createTags - doPost` with the following body: ```auto { "basePath": "[Sample_Tags]/Writeable", "tags": [ { "name": "DeviceEUI", "opcItemPath" : "ns=2;s=[Sample_Tags]_Meta:Writeable/DeviceEUI", "opcServer": "Ignition OPC UA Server", "valueSource": "opc" } ], "collisionPolicy": "o" } ``` The tag is created with the following result: (192 = “good”) ```auto [ { "code": 192 } ] ``` If I want to write data to the tag using `tag - doPost` with the following body: ```auto { "paths": ["[Sample_Tags]/Writeable/DeviceEUI", "[Sample_Tags]/Writeable/WriteableBoolean1"], "values": [12345, false] } ``` I get the following message: ```auto [ { "code": -2147483136, "diagnosticMessage": "Bad_NotWritable: The access level does not allow writing to the Node." }, { "code": 192 } ] ``` So the predefined tag WriteableBoolean1 has a result of 192 = “good”. The other tag DeviceEUI that I defined myself gets an error message. I suspect this is because I am trying to write to a tag which does not originates from a device that is defined in Ignition? If so, how can I write to a tag which I have created dynamically from an external program (using the Web Dev API) and write to it? (using the same Web Dev API) Thanks, Simon. ---
**Author:** ![Kevin.Herron](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kevin.herron/32/7259_2.png) [@Kevin.Herron](https://forum.inductiveautomation.com/u/Kevin.Herron)\ **Post date:** [April 28, 2022, 4:36pm UTC](https://forum.inductiveautomation.com/t/bad-notwritable-the-access-level-does-not-allow-writing-to-the-node/59005/2 "2022-04-28T16:36:28Z")
You’re creating an OPC Tag pointing to an address in the simulator driver that doesn’t exist. If you want to create an arbitrary tag then just create a Memory Tag instead, and don’t try to pretend it exists as part of some device/driver you don’t control. ---
**Author:** ![Simon.de.Kraa](https://avatars.discourse-cdn.com/v4/letter/s/82dd89/32.png) [@Simon.de.Kraa](https://forum.inductiveautomation.com/u/Simon.de.Kraa)\ **Post date:** [April 28, 2022, 4:59pm UTC](https://forum.inductiveautomation.com/t/bad-notwritable-the-access-level-does-not-allow-writing-to-the-node/59005/3 "2022-04-28T16:59:01Z")
Thanks Kevin. Specifying `"valueSource": "memory"` did the trick… ```auto { "basePath": "[Sample_Tags]/Writeable", "tags": [ { "name": "DeviceEUI", "opcItemPath" : "ns=2;s=[Sample_Tags]_Meta:Writeable/DeviceEUI", "opcServer": "Ignition OPC UA Server", "valueSource": "memory" } ], "collisionPolicy": "o" } ``` Another question though. Where can I find all the settings for a tag definition and their explanations? The reason why I am asking is the difficulty I have with e.g. the dataType property. See below. If I try for example to specify the data type with `"dataType": "string"` as follows: ```auto { "basePath": "[Sample_Tags]/Writeable", "tags": [ { "name": "DeviceEUI", "dataType": "string", "opcItemPath" : "ns=2;s=[Sample_Tags]_Meta:Writeable/DeviceEUI", "opcServer": "Ignition OPC UA Server", "valueSource": "memory" } ], "collisionPolicy": "o" } ``` I do see the data type is string in the OPC client: ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/6/5/65d33fe459bbb67725062acf6ca48587c880b1ce.png) But in the designer it is set to None: ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/9/0/90625e5fbcc9c1f28ade349d77cb534ddd9cfdfa.png) And if I try to write to the tag with: ```auto { "paths": ["[Sample_Tags]/Writeable/DeviceEUI"], "values": ["testing"] } ``` I get: ```auto [ { "code": -1073741052, "diagnosticMessage": "Error trying to coerce 'testing' to a number." } ] ``` So if there is a complete overview of all the properties of the tag definition that would be a great help! Thanks. ---
**Author:** ![Kevin.Herron](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kevin.herron/32/7259_2.png) [@Kevin.Herron](https://forum.inductiveautomation.com/u/Kevin.Herron)\ **Post date:** [April 28, 2022, 5:10pm UTC](https://forum.inductiveautomation.com/t/bad-notwritable-the-access-level-does-not-allow-writing-to-the-node/59005/4 "2022-04-28T17:10:41Z")
These doc pages should be useful: [https://docs.inductiveautomation.com/display/DOC81/system.tag.configure](https://docs.inductiveautomation.com/display/DOC81/system.tag.configure) [https://docs.inductiveautomation.com/display/DOC81/Tag+Properties](https://docs.inductiveautomation.com/display/DOC81/Tag+Properties) If you find the “Data Type” tag property there’s a list of valid values in its Description column. In your case I’m guessing it’s just a case sensitivity issue and you should be using `String`, not `string`. All the OPC-related properties you cited in your last example should be removed as well, they don’t apply to Memory Tags.