# How I can trigger inject node with input signal?
**URL:** https://discourse.nodered.org/t/how-i-can-trigger-inject-node-with-input-signal/57229
**Category:** General
**Created:** [25 January 2022 22:29 UTC](https://discourse.nodered.org/t/how-i-can-trigger-inject-node-with-input-signal/57229 "2022-01-25T22:29:54Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@maliheh.amirfakhry](https://discourse.nodered.org/u/maliheh.amirfakhry)
#### Post date: [25 January 2022 22:29 UTC](https://discourse.nodered.org/t/how-i-can-trigger-inject-node-with-input-signal/57229/1 "2022-01-25T22:29:54Z")
Hi, First of all, I have to say thank you for accepting me to this forum and sorry if my English is bad. I have a project with node-red and raspberry pi, I want to send an input signal to raspberry pi from a PLC and see the signal in a TCP server ( Hercules ). With inject node I can see the signal (1, 0) in Hercules at a specified time ( interval, interval between times, ...) but it doesn't work for me, What I need is to see the signal whenever it changes from 5 volts to 0 volts and vice versa. Please let me know if you have any suggestion? Thanks 🙂
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### Author:  [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)
#### Post date: [26 January 2022 10:44 UTC](https://discourse.nodered.org/t/how-i-can-trigger-inject-node-with-input-signal/57229/2 "2022-01-26T10:44:47Z")
Can you show us the values returned from the PLC?
Can you confirm the values you want to send over TCP (strings? booleans? bytes?)
Can you confirm I understand your requirements ...
1. When value from PLC changes from EXACTLY `5` to `0`
- Send `0` as a byte value to the TCP node - ONCE ONLY (until value changes)
2. When value from PLC changes from EXACTLY `0` to `5`
- Send `1` as a byte value to the TCP node - ONCE ONLY (until value changes)
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### Author:  [@maliheh.amirfakhry](https://discourse.nodered.org/u/maliheh.amirfakhry)
#### Post date: [26 January 2022 19:53 UTC](https://discourse.nodered.org/t/how-i-can-trigger-inject-node-with-input-signal/57229/3 "2022-01-26T19:53:20Z")
the value I see in TCP server is string. like input1:1,input2:1,input3:0,input4:1, ... but they are sent every 10 second according my injection nodes setting .
Yes, exactly my requirement is this.
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### Author:  [@system](https://discourse.nodered.org/u/system)
#### Post date: [27 March 2022 19:54 UTC](https://discourse.nodered.org/t/how-i-can-trigger-inject-node-with-input-signal/57229/4 "2022-03-27T19:54:13Z")
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