# How many serial requests blocs for one serial port

**URL:** https://discourse.nodered.org/t/how-many-serial-requests-blocs-for-one-serial-port/13687
**Category:** General
**Created:** [25 July 2019 12:40 UTC](https://discourse.nodered.org/t/how-many-serial-requests-blocs-for-one-serial-port/13687 "2019-07-25T12:40:43Z")
**Posts on this page:** 2
**Page:** 1

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### Author: ![Charlotte](https://avatars.discourse-cdn.com/v4/letter/c/65b543/32.png) [@Charlotte](https://discourse.nodered.org/u/Charlotte)
#### Post date: [25 July 2019 12:40 UTC](https://discourse.nodered.org/t/how-many-serial-requests-blocs-for-one-serial-port/13687/1 "2019-07-25T12:40:43Z")

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Hello,

I'm working on serial ports with a stirrer. I want to be able to start it, stop it and ask for the speed each 5 seconds. For each use case I have different commands to send and a different way to manage the answer from the stirrer.

So I created 2 serial requests blocs configured with my stirrer serial port. However only one is working at a time, the other one has a timeout.

If I copy paste the serial request to reset it and deploy then it is working fine but the other one is not anymore.

Is this the expected behaviour ? Should I have only one serial request for each port ? And then how should I manage different answers ?  
Is it the same for serial in and out, limited to one bloc ?

Thanks for your help

 ![Capture](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/2X/0/0270233af0104a93a1f089e7f43237b24cfe0d38.png)

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<div class="post-metadata">

### Author: ![ukmoose](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/ukmoose/32/13_2.png) [@ukmoose](https://discourse.nodered.org/u/ukmoose)
#### Post date: [25 July 2019 12:59 UTC](https://discourse.nodered.org/t/how-many-serial-requests-blocs-for-one-serial-port/13687/2 "2019-07-25T12:59:31Z")

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So in the serial request node, have you defined them as two distinct serial ports?  
Or have you one serial port that you are reusing?

Generally you can only have one "application" attached to a serial port, so if you use minicom for example and then start Node-RED it will find that the serial port is not available.

You could try to reuse the one config.  
If that doesn't work (i haven't tried) the serial request node info panel states

```auto
msg.payload is the response. If no response occured, this field is removed.
msg.status is "OK" in case a response is received, or "ERR_TIMEOUT" if a timeout occurs.
Any other field coming from the input will be preserved.

```

So you could set `msg.something` before the serial request node and then use a switch on the `msg.someting` value to direct the output