# Communicate with an old device

**URL:** <https://discourse.nodered.org/t/communicate-with-an-old-device/25932>\
**Category:** General\
**Created:** [2 May 2020 15:30 UTC](https://discourse.nodered.org/t/communicate-with-an-old-device/25932 "2020-05-02T15:30:00Z")\
**Posts on this page:** 18\
**Page:** 1

<div class="post-metadata">

**Author:** ![maccoa](https://avatars.discourse-cdn.com/v4/letter/m/a88e57/32.png) [@maccoa](https://discourse.nodered.org/u/maccoa)\
**Post date:** [2 May 2020 15:30 UTC](https://discourse.nodered.org/t/communicate-with-an-old-device/25932/1 "2020-05-02T15:30:00Z")

</div>

Hello .  
at work, I try to communicate with a fairly old device.  
on a pc window I used a serial port monitor, to see what was going on.  
with the modbus RTU protocol:

```auto
[21/04/2020 20:34:30]
Modbus Request (COM4)
Address: 1
Function: 3 (0x03) - Read Holding Registers
	Starting Address: 0
	Quantity: 1
Checksum: 33802(OK)
-------------------------------------
[21/04/2020 20:34:30]
Modbus Response (COM4)
Address: 1
Function: 3 (0x03) - Read Holding Registers
Checksum: 512(BAD)

```

the software that works with this device reads the data well. with modbus contrib, I send the same request and I have an error in length.

after I did a "dump" when reading a single channel. the software always sends the same .

```auto
[02/05/2020 14:51:52] Written data (COM2)
	

01 03 00 00 00 01 84 0a ......„.        

[02/05/2020 14:51:52] Read data (COM2)
	

01 03 02 00 15 79 8b .....y‹         

[02/05/2020 14:51:53] Written data (COM2)
	

01 03 00 00 00 01 84 0a ......„.        

[02/05/2020 14:51:53] Read data (COM2)
	

01 03 02 00 13 f9 89

```

avec node red , j'ai envoyé une command avec le node inject .

```auto
[
    {
        "id": "6e17b8ad.80e198",
        "type": "inject",
        "z": "88afcf0a.d8631",
        "name": "v1",
        "topic": "",
        "payload": "[\"0X01\",\"0x03\",\"0x00\",\"0x00\",\"0x00\",\"0x01\",\"0x84\",\"0x0a\"]",
        "payloadType": "bin",
        "repeat": "10",
        "crontab": "",
        "once": false,
        "onceDelay": 0.1,
        "x": 130,
        "y": 100,
        "wires": [
            [
                "22eca8d4.c696a8"
            ]
        ]
    }
]

```

I have an answer,

[2,0,34,56,93,1,3]

![Capture du 2020-05-02 17-25-56](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/4/7/47f579903948741913b72cd0d11079051993e341.png)

do you have any advice to try to understand where I'm doing something stupid

---

<div class="post-metadata">

**Author:** ![greengolfer](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/greengolfer/32/28276_2.png) [@greengolfer](https://discourse.nodered.org/u/greengolfer)\
**Post date:** [3 May 2020 05:47 UTC](https://discourse.nodered.org/t/communicate-with-an-old-device/25932/2 "2020-05-03T05:47:14Z")

</div>

The first debug information is COM2 and after that COM4. Assuming this is not the issue, usually with serial communication, when it is "wrong" it is often the configuration of the COM port which is not consistent. Speed, parity, length... If one is wrong, you receive (and send) garbage.  
So check the serial port parameters on both sides.  
GV

---

<div class="post-metadata">

**Author:** ![craigcurtin](https://avatars.discourse-cdn.com/v4/letter/c/94ad74/32.png) [@craigcurtin](https://discourse.nodered.org/u/craigcurtin)\
**Post date:** [3 May 2020 07:15 UTC](https://discourse.nodered.org/t/communicate-with-an-old-device/25932/3 "2020-05-03T07:15:39Z")

</div>

I would 2nd that - it appears you are getting a checksum error - if i had to guess i would say have a look at the serial port setup parameters - in particular what your stop bits are set for (1,2, or none).

As you are getting some correct and readable data it will probably be some of the setup of the port - not speed or it would all be garbled - so i would work my way through the sequence - show us what the setup of the com port looks like ? i.e. speed, parity, start and stop bits, xon/xoff etc

Craig

---

<div class="post-metadata">

**Author:** ![Steve-Mcl](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/steve-mcl/32/4826_2.png) [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)\
**Post date:** [3 May 2020 08:34 UTC](https://discourse.nodered.org/t/communicate-with-an-old-device/25932/4 "2020-05-03T08:34:09Z")

</div>

To me, it looks like you are reinventing the wheel.

From the screenshots you posted, the old device appears to be using modbus.  
Have you tried the [modbus](https://flows.nodered.org/node/node-red-contrib-modbus) nodes?

If that's what didn't work for you, perhaps when you tried it was set incorrectly?

What is this old device? Perhaps it has documentation of the protocol settings & com settings?

---

<div class="post-metadata">

**Author:** ![maccoa](https://avatars.discourse-cdn.com/v4/letter/m/a88e57/32.png) [@maccoa](https://discourse.nodered.org/u/maccoa)\
**Post date:** [3 May 2020 18:00 UTC](https://discourse.nodered.org/t/communicate-with-an-old-device/25932/5 "2020-05-03T18:00:23Z")

</div>

thank you for the information.

the device is a thermoclim 8/16, to consult it we use an old pc which is about to render the soul, through a moxa nport5110.  
Of course, we no longer have the documentation or the software installation CD and I couldn't find anything on the web.

thermoclim8 / 16 ------- rs232 ------ Nport5110 ------- ethernet ------- pc.

on the old pc i tried to install serial port monitor but it made everything crash. then on another pc, I copied the thermosoft directory, put various dll and ocx and I can launch the software and have serial port monitor at the same time.

I reconfigure the serial port.  
baud rate 9600  
data bit 8  
Stop bits 1  
Parity none  
Flow control none  
FIFO none

with node red I can read with modbus read without CRC error, it's already a good point.  
now I have to find the addresses that correspond to the measurement channels.

when I log each channel I noted the order sent

v1 = 01 03 00 00 00 01 84 0a  
v3 = 01 03 00 00 00 03 05cb  
/  
/  
v15 = 01 03 00 00 00 0f 05 ce

01= ID  
03= read holding register  
last 2 digit crc ?  
01 03 .... 0f adress ?

or I really have it all wrong, how to find address and quantity in node red modbus contrib?  
thanks again

---

<div class="post-metadata">

**Author:** ![Steve-Mcl](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/steve-mcl/32/4826_2.png) [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)\
**Post date:** [3 May 2020 19:30 UTC](https://discourse.nodered.org/t/communicate-with-an-old-device/25932/6 "2020-05-03T19:30:55Z")

</div>

I see.

There are modbus decoders like this one...  
[https://rapidscada.net/modbus/ModbusParser.aspx](https://rapidscada.net/modbus/ModbusParser.aspx)

Example...

 ![Screenshot_20200503-202756](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/c/e/ce602c6f73a707efa11753fff81858764814949d.jpeg)

You can paste the hexadecimal values for send and receive to help you understand addresses and FNC codes.

---

<div class="post-metadata">

**Author:** ![rromele](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/rromele/32/18431_2.png) [@rromele](https://discourse.nodered.org/u/rromele)\
**Post date:** [3 May 2020 19:58 UTC](https://discourse.nodered.org/t/communicate-with-an-old-device/25932/7 "2020-05-03T19:58:23Z")

</div>

> [@maccoa](#):
>
> Ho una risposta
> 
> [2,0,34,56,93,1,3]

from what you write in the first post, your device does not seem to send a large amount of data, I recommend using a modbus network scanner to identify what and where it writes.  
From the string "01 03 xx yy 0f" xx = address yy == quantity.  
The format of the data you receive (Int, floating point, etc.) is also important because it could be that the answer you receive:  
[2,0,34,56,93,1,3]  
is correct but you have to recompose the arrays in the native transmission format.

---

<div class="post-metadata">

**Author:** ![maccoa](https://avatars.discourse-cdn.com/v4/letter/m/a88e57/32.png) [@maccoa](https://discourse.nodered.org/u/maccoa)\
**Post date:** [4 May 2020 18:26 UTC](https://discourse.nodered.org/t/communicate-with-an-old-device/25932/8 "2020-05-04T18:26:21Z")

</div>

Thank you for your answers .

I manage to read the 1st address but when I want to read all the addresses it doesn't work anymore.

1st address reading

 ![q1](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/7/8/78d025245420e1d4cbb48466596d23f07e539d47.png)

reading 16 address

 ![q16](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/1/1/11a9476947e38d381221df826f6e4067010613a4.png)

and the log .

```
4 May 20:21:20 - [info] Started modified nodes
4 May 20:21:20 - [trace] runtime event: {"id":"runtime-deploy","payload":{"revision":"d02b2428254038460c7f078a0c0272b1"},"retain":true} **contribModbus:core:client** Client -> {"info":"pushed to Queue by Unit-Id","message":{"unitid":1,"fc":3,"address":0,"quantity":16,"messageId":"5eb05d24b453533edb098db3","emptyMsgOnFail":true},"unitId":1} Serial@/dev/ttyr00:9600bit/s default Unit-Id: 1 +17s **contribModbus:core:client** Client -> {"info":"queued read msg","message":{"unitid":1,"fc":3,"address":0,"quantity":16,"messageId":"5eb05d24b453533edb098db3","emptyMsgOnFail":true},"state":"connected","queueLength":1} Serial@/dev/ttyr00:9600bit/s default Unit-Id: 1 +0ms **contribModbus:core:client** Client -> queueing Serial@/dev/ttyr00:9600bit/s default Unit-Id: 1 +1ms **contribModbus:core:client** Client -> sending Serial@/dev/ttyr00:9600bit/s default Unit-Id: 1 +0ms **contribModbus:core:client** Client -> {"type":"sequential dequeue command","unitId":1,"isValidUnitId":true,"sendingAllowed":true,"serialSendingAllowed":true} Serial@/dev/ttyr00:9600bit/s default Unit-Id: 1 +3s **contribModbus:core:client** Client -> {"type":"send queue data to Modbus","unitId":1,"queueLength":1,"sendingAllowed":true,"serialSendingAllowed":false} Serial@/dev/ttyr00:9600bit/s default Unit-Id: 1 +1ms **contribModbus:core:client** Client -> {"info":"read msg via Modbus","message":{"unitid":1,"fc":3,"address":0,"quantity":16,"messageId":"5eb05d24b453533edb098db3","emptyMsgOnFail":true},"queueUnitId":1,"timeout":2500,"state":"sending"} Serial@/dev/ttyr00:9600bit/s default Unit-Id: 1 +0ms **modbus-serial** { **modbus-serial** action: 'send serial rtu buffered', **modbus-serial** data: <Buffer 01 03 00 00 00 10 44 06>, **modbus-serial** unitid: 1, **modbus-serial** functionCode: 3 **modbus-serial** } +27s **contribModbus:core:client** Client -> {"state":"sending","message":"dequeue command done serial","delay":2500} Serial@/dev/ttyr00:9600bit/s default Unit-Id: 1 +1ms **modbus-serial** { **modbus-serial** action: 'receive serial rtu buffered port', **modbus-serial** data: <Buffer 01>, **modbus-serial** buffer: <Buffer 01> **modbus-serial** } +395ms **modbus-serial** { **modbus-serial** action: 'receive serial rtu buffered port', **modbus-serial** data: <Buffer 03 02 00 e1>, **modbus-serial** buffer: <Buffer 01 03 02 00 e1> **modbus-serial** } +4ms **modbus-serial** { **modbus-serial** action: 'receive serial rtu buffered port', **modbus-serial** data: <Buffer 78 0c>, **modbus-serial** buffer: <Buffer 01 03 02 00 e1 78 0c> **modbus-serial** } +6ms **contribModbus:core:client** Client -> {"info":"queue response activate sending","sendingAllowed":true,"serialSendingAllowed":true,"queueUnitId":1} Serial@/dev/ttyr00:9600bit/s default Unit-Id: 1 +3s **contribModbus:core:client** Client -> sending Serial@/dev/ttyr00:9600bit/s default Unit-Id: 1 +1ms **modbus-serial** modbusErrorHandling:Timed out +22s **contribModbus:core:client** Client -> failed Serial@/dev/ttyr00:9600bit/s default Unit-Id: 1 +0ms
4 May 20:21:29 - [warn] [modbus-client:moxa] Client -> fsm failed state after sending Get More About It By Logging Serial@/dev/ttyr00:9600bit/s default Unit-Id: 1
4 May 20:21:29 - [warn] [modbus-flex-getter:5f019902.1af158] Modbus Failure On State sending Get More About It By Logging **contribModbus:core:client** Client -> broken Serial@/dev/ttyr00:9600bit/s default Unit-Id: 1 +1ms
4 May 20:21:29 - [warn] [modbus-client:moxa] Client -> fsm broken state after failed Get More About It By Logging Serial@/dev/ttyr00:9600bit/s default Unit-Id: 1 **contribModbus:core:client** Client -> reconnecting Serial@/dev/ttyr00:9600bit/s default Unit-Id: 1 +0ms
4 May 20:21:29 - [warn] [modbus-client:moxa] Client -> fsm reconnect state after broken Get More About It By Logging Serial@/dev/ttyr00:9600bit/s default Unit-Id: 1 **contribModbus:flex:getter** Timed out +27s
4 May 20:21:29 - [error] [modbus-flex-getter:5f019902.1af158] Timed out **contribModbus:core** Message Not Found undefined +27s **contribModbus:core:client** Client -> reconnecting Serial@/dev/ttyr00:9600bit/s default Unit-Id: 1 +2ms **contribModbus:core:client** Client -> init Serial@/dev/ttyr00:9600bit/s default Unit-Id: 1 +2s
4 May 20:21:31 - [warn] [modbus-client:moxa] Client -> fsm init state after reconnecting Serial@/dev/ttyr00:9600bit/s default Unit-Id: 1
4 May 20:21:31 - [warn] [modbus-client:moxa] Client -> fsm init in 2000 ms Serial@/dev/ttyr00:9600bit/s default Unit-Id: 1 **contribModbus:core:client** Client -> connection close sent Serial@/dev/ttyr00:9600bit/s default Unit-Id: 1 +2s **contribModbus:core:client** Client -> RTU buffered port serial Serial@/dev/ttyr00:9600bit/s default Unit-Id: 1 +1ms **contribModbus:core:client** Client -> connection closed Serial@/dev/ttyr00:9600bit/s default Unit-Id: 1 +6ms **contribModbus:core:client** Client -> opened Serial@/dev/ttyr00:9600bit/s default Unit-Id: 1 +47ms **contribModbus:core:client** Client -> time to open Unit 1 Serial@/dev/ttyr00:9600bit/s default Unit-Id: 1 +1s **modbus-serial** modbus connection opened +5s **contribModbus:core:client** Client -> connected Serial@/dev/ttyr00:9600bit/s default Unit-Id: 1 +1ms
4 May 20:21:34 - [warn] [modbus-client:moxa] Client -> fsm connected after state opened Get More About It By Logging Serial@/dev/ttyr00:9600bit/s default Unit-Id: 1
```

an idea of what can go wrong?

---

<div class="post-metadata">

**Author:** ![Steve-Mcl](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/steve-mcl/32/4826_2.png) [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)\
**Post date:** [4 May 2020 18:35 UTC](https://discourse.nodered.org/t/communicate-with-an-old-device/25932/9 "2020-05-04T18:35:04Z")

</div>

Did the original request 16 items?

Perhaps the old device doesn't have 16 registers?

---

<div class="post-metadata">

**Author:** ![maccoa](https://avatars.discourse-cdn.com/v4/letter/m/a88e57/32.png) [@maccoa](https://discourse.nodered.org/u/maccoa)\
**Post date:** [4 May 2020 18:45 UTC](https://discourse.nodered.org/t/communicate-with-an-old-device/25932/10 "2020-05-04T18:45:09Z")

</div>

I think so

| Part of Data Package | Description | Value |
| --- | --- | --- |
| 01 | Slave address | 0x01 (1) |
| 03 | Function code | 0x03 (3) - Read Holding Registers |
| 00 00 | Starting address | 0x0001 (1) |
| 00 10 | Quantity | 0x0010 (16) |
| 44 06 | CRC | 0x4406 (17414) |

---

<div class="post-metadata">

**Author:** ![Steve-Mcl](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/steve-mcl/32/4826_2.png) [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)\
**Post date:** [4 May 2020 18:51 UTC](https://discourse.nodered.org/t/communicate-with-an-old-device/25932/11 "2020-05-04T18:51:23Z")

</div>

Your code starts at address 0 by the post above says address 1.

Some implementations of modbus mix this up (or add 1 or deduct 1 from your address to compensate). Try changing the address.

Also, try accessing only 15. Just to see if you can get things moving.

Edit, just looked at logs seems the address is ok.

Is there any way of adding a delay in the serial line? Try adding 30ms or maybe 100ms.

---

<div class="post-metadata">

**Author:** ![maccoa](https://avatars.discourse-cdn.com/v4/letter/m/a88e57/32.png) [@maccoa](https://discourse.nodered.org/u/maccoa)\
**Post date:** [5 May 2020 16:56 UTC](https://discourse.nodered.org/t/communicate-with-an-old-device/25932/12 "2020-05-05T16:56:55Z")

</div>

> Is there any way of adding a delay in the serial line? Try adding 30ms or maybe 100ms.

I looked in the box and the thermoclim menus, I found nothing on modbus communication.  
I am currently testing with inject nodes.

 ![Capture du 2020-05-05 18-43-01](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/e/0/e06321849d7c6a023c785a0a219ec12b4a8c284f.png)

I am currently testing with inject nodes.  
I put a 1second screen between each and I get an answer for each channel, but I'm not sure of the values, I have the impression that they vary enormously.

 ![Capture du 2020-05-05 18-55-10](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/7/1/71fe39be542e14c09c551f7332109875cb953b8c.png)

I will see tomorrow morning

---

<div class="post-metadata">

**Author:** ![maccoa](https://avatars.discourse-cdn.com/v4/letter/m/a88e57/32.png) [@maccoa](https://discourse.nodered.org/u/maccoa)\
**Post date:** [9 May 2020 07:21 UTC](https://discourse.nodered.org/t/communicate-with-an-old-device/25932/13 "2020-05-09T07:21:58Z")

</div>

Do you think we can do it with the stty command?

> stty -a -F /dev/ttyr00  
> speed 9600 baud; rows 0; columns 0; line = 0;  
> intr = ^C; quit = ^; erase = ^?; kill = ^U; eof = ^D; eol = ;  
> eol2 = ; swtch = ; start = ^Q; stop = ^S; susp = ^Z; rprnt = ^R;  
> werase = ^W; lnext = ^V; discard = ^O; min = 1; time = 0;  
> -parenb -parodd -cmspar cs8 hupcl -cstopb cread clocal -crtscts  
> -ignbrk -brkint ignpar -parmrk -inpck -istrip -inlcr -igncr -icrnl -ixon -ixoff  
> -iuclc -ixany -imaxbel -iutf8  
> -opost -olcuc -ocrnl -onlcr -onocr -onlret -ofill -ofdel nl0 cr0 tab0 bs0 vt0 ff0  
> -isig -icanon -iexten -echo -echoe -echok -echonl -noflsh -xcase -tostop -echoprt  
> -echoctl -echoke -flusho -extproc

I try to understand the stty documentation but I admit that I don't understand much

---

<div class="post-metadata">

**Author:** ![Steve-Mcl](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/steve-mcl/32/4826_2.png) [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)\
**Post date:** [9 May 2020 08:08 UTC](https://discourse.nodered.org/t/communicate-with-an-old-device/25932/14 "2020-05-09T08:08:10Z")

</div>

Are you still using modbus nodes or trying to get data yourself with serial node?

---

<div class="post-metadata">

**Author:** ![maccoa](https://avatars.discourse-cdn.com/v4/letter/m/a88e57/32.png) [@maccoa](https://discourse.nodered.org/u/maccoa)\
**Post date:** [9 May 2020 08:53 UTC](https://discourse.nodered.org/t/communicate-with-an-old-device/25932/15 "2020-05-09T08:53:52Z")

</div>

for the commande whit stty

> chris@lmrasp:~$ stty -F /dev/ttyr00 -icanon time 250  
> chris@lmrasp:~$ stty -a -F /dev/ttyr00  
> speed 9600 baud; rows 0; columns 0; line = 0;  
> intr = ^C; quit = ^; erase = ^?; kill = ^U; eof = ^D; eol = ; eol2 = ;  
> swtch = ; start = ^Q; stop = ^S; susp = ^Z; rprnt = ^R; werase = ^W; lnext = ^V;  
> discard = ^O; min = 1; time = 250;  
> -parenb -parodd -cmspar cs8 hupcl -cstopb cread clocal -crtscts  
> -ignbrk -brkint ignpar -parmrk -inpck -istrip -inlcr -igncr -icrnl -ixon -ixoff -iuclc  
> -ixany -imaxbel -iutf8  
> -opost -olcuc -ocrnl -onlcr -onocr -onlret -ofill -ofdel nl0 cr0 tab0 bs0 vt0 ff0  
> -isig -icanon -iexten -echo -echoe -echok -echonl -noflsh -xcase -tostop -echoprt -echoctl  
> -echoke -flusho -extproc

I tried :  
address 0 quantity 1 -\> ok  
address 1 quantity 1 -\> ok

 ![a0q1](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/9/9/99917a13513c29116456c27f9f64d5c18eb3bb67.png)  
 ![a1q1](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/4/d/4da519fca69b697c41686b72c2687d7d4383fdb3.png)  
channel 2 is deactivated which would correspond to address 1 (0)

I know that address 18 or 19, it depends if it starts from 0 or 1, quantity 16 must answer me"local info"

 ![a18q16](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/c/c/cca3f0b6e1ee262fb27ea78d2135f94778e8708b.png)  
if I lie address 19 it's the same result

with this modbus flex getter

 ![inject](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/d/8/d8455752f366993493902921b18ce06220cee7a2.png)

| Part of Data Package | Description | Value |
| --- | --- | --- |
| 01 | Slave address | 0x01 (1) |
| 03 | Function code | 0x03 (3) - Read Holding Registers |
| 00 12 | Starting address | 0x0013 (19) |
| 00 10 | Quantity | 0x0010 (16) |
| E4 03 | CRC | 0xE403 (58371) |
| spying on com port tells me | | |

> [02/05/2020 08:42:38] Written data (COM2)  
> 01 03 00 12 00 10 e4 03 ......д.
> 
> [02/05/2020 08:42:38] Read data (COM2)
> 
> 01 03 0c 6c 6f 63 61 6c 20 69 6e 66 6f 20 20 6a ...local info j
> 
> 14

| Part of Data Package | Description | Value |
| --- | --- | --- |
| 01 | Slave address | 0x01 (1) |
| 03 | Function code | 0x03 (3) - Read Holding Registers |
| 0C | Byte count | 0x0C (12) |
| 6C 6F 63 61 6C 20 69 6E 66 6F 20 20 | Register value | 0x6C6F (27759), 0x6361 (25441), 0x6C20 (27680), 0x696E (26990), 0x666F (26223), 0x2020 (8224) |
| 6A 14 | CRC | 0x6A14 (27156) |

![hex as](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/5/7/57e7c0ecd09b861e42dd6fcef7c3ace74ce23d16.png)  
I had a lot less problem to dialogue with my boiler in modbus ascii 😃

---

<div class="post-metadata">

**Author:** ![maccoa](https://avatars.discourse-cdn.com/v4/letter/m/a88e57/32.png) [@maccoa](https://discourse.nodered.org/u/maccoa)\
**Post date:** [9 May 2020 12:54 UTC](https://discourse.nodered.org/t/communicate-with-an-old-device/25932/16 "2020-05-09T12:54:23Z")

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well, I don't really know how I did it but with 2 terminal, the first with cat / dev .... and the second with echo -e, I managed to send data and receive the right answer.  
would it be possible that i don't have the right versions  
npm 6.14.4  
Node-RED version: v1.0.5  
Node.js version: v12.16.3  
node-red-contrib-modbus 5.10.1

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<div class="post-metadata">

**Author:** ![maccoa](https://avatars.discourse-cdn.com/v4/letter/m/a88e57/32.png) [@maccoa](https://discourse.nodered.org/u/maccoa)\
**Post date:** [16 May 2020 06:05 UTC](https://discourse.nodered.org/t/communicate-with-an-old-device/25932/17 "2020-05-16T06:05:07Z")

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finally, with a serial request it works.  
as soon as I try with modbus flex getter I have errors.

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<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/1X/d073cd938eafa2e558d7c2cd59003b3ef4963033.png) [@system](https://discourse.nodered.org/u/system)\
**Post date:** [15 July 2020 06:05 UTC](https://discourse.nodered.org/t/communicate-with-an-old-device/25932/18 "2020-07-15T06:05:13Z")

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