# How to write to two registers simultaneously using the FC 16
**URL:** https://discourse.nodered.org/t/how-to-write-to-two-registers-simultaneously-using-the-fc-16/93191
**Category:** Dashboard
**Created:** [16 November 2024 19:50 UTC](https://discourse.nodered.org/t/how-to-write-to-two-registers-simultaneously-using-the-fc-16/93191 "2024-11-16T19:50:58Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@Desmond-Zeh](https://discourse.nodered.org/u/Desmond-Zeh)
#### Post date: [16 November 2024 19:50 UTC](https://discourse.nodered.org/t/how-to-write-to-two-registers-simultaneously-using-the-fc-16/93191/1 "2024-11-16T19:50:58Z")
Hello Team!
I’ve developed a small supervision system for my generator using node red nodes. On the system, in order to reset an alarm, I’ll have to send two values ( 35707 and 29828) to two separate registers ( 4104 and 4105) simultaneously. I’ve tried this using the FC 16 function but no positive result.
Here below is the code
```auto
value: 35707,
'fc': 16,
'unitid': 1,
'address': 4104 ,
'quantity': 1
}, {
value: 29828,
'fc': 16,
'unitid': 1,
'address': 4105 ,
'quantity': 1
}]``
This returns an error code ''Wrong FC used''.
I think it has to do with the FC 16 I've used.
But, how do I get around this. Please any help will be highly appreciated.
```
---
### Author:  [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)
#### Post date: [16 November 2024 19:59 UTC](https://discourse.nodered.org/t/how-to-write-to-two-registers-simultaneously-using-the-fc-16/93191/2 "2024-11-16T19:59:02Z")
As the built in help says:
> **msg.payload** must be an array`[]` of comma separated values between 0:65535 each
And there is a built in demo
---
### Author:  [@Desmond-Zeh](https://discourse.nodered.org/u/Desmond-Zeh)
#### Post date: [16 November 2024 21:10 UTC](https://discourse.nodered.org/t/how-to-write-to-two-registers-simultaneously-using-the-fc-16/93191/3 "2024-11-16T21:10:23Z")
Thank you Steve.
I got it.
---
### Author:  [@system](https://discourse.nodered.org/u/system)
#### Post date: [30 November 2024 21:10 UTC](https://discourse.nodered.org/t/how-to-write-to-two-registers-simultaneously-using-the-fc-16/93191/4 "2024-11-30T21:10:43Z")
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