# Read Registers From Modbus Not in Sequence
**URL:** https://discourse.nodered.org/t/read-registers-from-modbus-not-in-sequence/51710
**Category:** General
**Created:** [30 September 2021 10:23 UTC](https://discourse.nodered.org/t/read-registers-from-modbus-not-in-sequence/51710 "2021-09-30T10:23:38Z")
**Posts on this page:** 17
**Page:** 1
### Author:  [@ELParreira](https://discourse.nodered.org/u/ELParreira)
#### Post date: [30 September 2021 10:23 UTC](https://discourse.nodered.org/t/read-registers-from-modbus-not-in-sequence/51710/1 "2021-09-30T10:23:38Z")
Hello,
I want to read multiple registers from modbus that are not in a sequence, what would be the best way? Is there any modbus node that I can use to do it, or shoud I use two modbus flex read and then join. I was trying the last solution without any luck joining the data array to after process in the buffer parser.
Thank you for any help provided.
Cheers
---
### Author:  [@UnborN](https://discourse.nodered.org/u/UnborN)
#### Post date: [30 September 2021 14:11 UTC](https://discourse.nodered.org/t/read-registers-from-modbus-not-in-sequence/51710/2 "2021-09-30T14:11:34Z")
Hello ..
> [@ELParreira](#):
>
> I want to read multiple registers from modbus that are not in a sequence
I think with the latest version of Modbus nodes v.5.14.1 there is a new node called Modbus-Flex-Sequencer that supposedly does just that .. do sequential reads .. but i havent tested it yet.
Whats wrong with the setup you have now ? .. what problem do you have joining the messages with the Join node ? You havent shared your flow to see how you setup your join node but if you add the Buffer parser nodes after each of your Modbus Flex getters and then wire those to a Join node with the following settings it should theoretically work.
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### Author:  [@Colin](https://discourse.nodered.org/u/Colin)
#### Post date: [30 September 2021 14:30 UTC](https://discourse.nodered.org/t/read-registers-from-modbus-not-in-sequence/51710/3 "2021-09-30T14:30:35Z")
It might be better to wire the modbus nodes in series. So after the first one save the data to a message property and then wire to the function node and second modbus node, then you will have a message with both results in it. The modbus node should not destroy the saved property. Then you won't have two modbus nodes trying to do things at (virtually) the same time, which is safer.
---
### Author:  [@ELParreira](https://discourse.nodered.org/u/ELParreira)
#### Post date: [30 September 2021 14:42 UTC](https://discourse.nodered.org/t/read-registers-from-modbus-not-in-sequence/51710/4 "2021-09-30T14:42:39Z")
> [@UnborN](#):
>
> I think with the latest version of Modbus nodes v.5.14.1 there is a new node called Modbus-Flex-Sequencer that supposedly does just that .. do sequential reads .. but i havent tested it yet.
>
> Whats wrong with the setup you have now ? .. what problem do you have joining the mes
I'll give sequencer a try and then let you know. Cheers
---
### Author:  [@ELParreira](https://discourse.nodered.org/u/ELParreira)
#### Post date: [30 September 2021 14:44 UTC](https://discourse.nodered.org/t/read-registers-from-modbus-not-in-sequence/51710/5 "2021-09-30T14:44:24Z")
Sorry Colin, I didn't understood your suggestion. I'm new to Node Red. But enjoying it more everyday. Cheers
---
### Author:  [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)
#### Post date: [30 September 2021 14:48 UTC](https://discourse.nodered.org/t/read-registers-from-modbus-not-in-sequence/51710/6 "2021-09-30T14:48:26Z")
@Colin is talking about wiring all nodes in series, like this: [Modbus Serial - Whole bus disconnects when one device drops - #16 by Steve-Mcl](https://discourse.nodered.org/t/modbus-serial-whole-bus-disconnects-when-one-device-drops/48555/16)
---
### Author:  [@Colin](https://discourse.nodered.org/u/Colin)
#### Post date: [30 September 2021 14:53 UTC](https://discourse.nodered.org/t/read-registers-from-modbus-not-in-sequence/51710/7 "2021-09-30T14:53:16Z")
I haven't got the modbus nodes installed so can only mock up an image to show the flow.
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### Author:  [@UnborN](https://discourse.nodered.org/u/UnborN)
#### Post date: [30 September 2021 15:05 UTC](https://discourse.nodered.org/t/read-registers-from-modbus-not-in-sequence/51710/8 "2021-09-30T15:05:21Z")
> [@ELParreira](#):
>
> I'll give sequencer a try and then let you know.
I did a quick test with the Modbus-Flex-Sequencer and it doesnt work 😉 (i think its still under development)
Even if it did work, it would be a headache to route its results to individual buffer parsers to convert your values, so the best approach is what Colin and Steve recommended.
---
### Author:  [@ELParreira](https://discourse.nodered.org/u/ELParreira)
#### Post date: [30 September 2021 16:43 UTC](https://discourse.nodered.org/t/read-registers-from-modbus-not-in-sequence/51710/9 "2021-09-30T16:43:16Z")
Also arrived to the same conclusion.
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### Author:  [@PLCMercenary](https://discourse.nodered.org/u/PLCMercenary)
#### Post date: [30 September 2021 18:00 UTC](https://discourse.nodered.org/t/read-registers-from-modbus-not-in-sequence/51710/10 "2021-09-30T18:00:27Z")
I parse a CSV with the registers i want to read, and their context, then loop each of the points into the flex getter node for a read and store all the register values into flow or global vars.
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### Author:  [@UnborN](https://discourse.nodered.org/u/UnborN)
#### Post date: [30 September 2021 19:03 UTC](https://discourse.nodered.org/t/read-registers-from-modbus-not-in-sequence/51710/11 "2021-09-30T19:03:48Z")
> [@PLCMercenary](#):
>
> then loop each of the points into the flex getter node
This sounds like a good approach. I wanted to ask whether you do a small delay when sending the messages this way or do you let the Flex getter node queue and delay the msgs with its settings.
---
### Author:  [@ELParreira](https://discourse.nodered.org/u/ELParreira)
#### Post date: [1 October 2021 14:24 UTC](https://discourse.nodered.org/t/read-registers-from-modbus-not-in-sequence/51710/12 "2021-10-01T14:24:54Z")
I'm sorry to bother again. But I understood your idea, just can't seem to make it work. Having real problems joining at the end the two messages. I need an array (or buffer) to use buffer parser and get the variables, that is way I want to join them together.
Cheers
---
### Author:  [@ELParreira](https://discourse.nodered.org/u/ELParreira)
#### Post date: [1 October 2021 15:52 UTC](https://discourse.nodered.org/t/read-registers-from-modbus-not-in-sequence/51710/13 "2021-10-01T15:52:41Z")
I think I found the best way to do it. This will be to read around 100 modbus equipments. I hope it won't brake down.
```auto
[{"id":"7b5ce34010b47634","type":"tab","label":"Modbus Sequence","disabled":false,"info":""},{"id":"1a61223919d36fa1","type":"inject","z":"7b5ce34010b47634","name":"","props":[{"p":"payload"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payloadType":"date","x":120,"y":160,"wires":[["a3b64b9f1004af66"]]},{"id":"a3b64b9f1004af66","type":"function","z":"7b5ce34010b47634","name":"DirisA10#5 Common","func":"msg.payload = { value: msg.payload,\n'fc': 3,\n'unitid': 22, \n'address': 2 , \n'quantity': 6 }; \nreturn msg;","outputs":1,"noerr":0,"initialize":"","finalize":"","libs":[],"x":340,"y":160,"wires":[["775615de01c50f58"]]},{"id":"775615de01c50f58","type":"modbus-flex-getter","z":"7b5ce34010b47634","name":"Modbus Read #22","showStatusActivities":true,"showErrors":true,"logIOActivities":false,"server":"8643327cb6aae6be","useIOFile":false,"ioFile":"","useIOForPayload":false,"emptyMsgOnFail":false,"keepMsgProperties":true,"x":570,"y":160,"wires":[[],["465426bf347e7399"]]},{"id":"465426bf347e7399","type":"change","z":"7b5ce34010b47634","name":"","rules":[{"t":"move","p":"payload.data","pt":"msg","to":"data01","tot":"msg"}],"action":"","property":"","from":"","to":"","reg":false,"x":950,"y":160,"wires":[["c571b7a2a8b6bb89"]]},{"id":"c571b7a2a8b6bb89","type":"function","z":"7b5ce34010b47634","name":"DirisA10#5 Energies","func":"msg.payload = { value: msg.payload,\n'fc': 3,\n'unitid': 22, \n'address': 6687 , \n'quantity': 2 }; \nreturn msg;","outputs":1,"noerr":0,"initialize":"","finalize":"","libs":[],"x":340,"y":260,"wires":[["9596fd4115a8992c"]]},{"id":"9596fd4115a8992c","type":"modbus-flex-getter","z":"7b5ce34010b47634","name":"Modbus Read #22","showStatusActivities":true,"showErrors":true,"logIOActivities":false,"server":"8643327cb6aae6be","useIOFile":false,"ioFile":"","useIOForPayload":false,"emptyMsgOnFail":false,"keepMsgProperties":true,"x":570,"y":260,"wires":[[],["e9fc5b56c604f2bd"]]},{"id":"342d9d605b8f0897","type":"function","z":"7b5ce34010b47634","name":"","func":"msg.counter = 'Counter#22'\nmsg.ts = msg.timestamp\nmsg.V1 = ((msg.data01[0] << 16) + msg.data01[1])*0.01\nmsg.V2 = ((msg.data01[2] << 16) + msg.data01[3])*0.01\nmsg.V3 = ((msg.data01[4] << 16) + msg.data01[5])*0.01\n\nmsg.Energy = ((msg.payload.data[0] << 16) + msg.payload.data[1])*0.01\n\nmsg.payload = {\n ts:msg.ts, \n V1:msg.V1,\n V2:msg.V2,\n V3:msg.V3,\n Energy:msg.Energy\n } \nreturn msg;","outputs":1,"noerr":0,"initialize":"","finalize":"","libs":[],"x":1040,"y":260,"wires":[["afedee5c5e9ff47f"]]},{"id":"e9fc5b56c604f2bd","type":"moment","z":"7b5ce34010b47634","name":"'yyyy-MM-DD hh:mm:ss'","topic":"","input":"","inputType":"date","inTz":"Europe/Lisbon","adjAmount":0,"adjType":"days","adjDir":"add","format":"'yyyy-MM-DD HH:mm:ss'","locale":"en-US","output":"timestamp","outputType":"msg","outTz":"Europe/Lisbon","x":790,"y":280,"wires":[["342d9d605b8f0897"]]},{"id":"afedee5c5e9ff47f","type":"debug","z":"7b5ce34010b47634","name":"","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"false","statusVal":"","statusType":"auto","x":1240,"y":280,"wires":[]},{"id":"8643327cb6aae6be","type":"modbus-client","name":"Modbus TCP","clienttype":"tcp","bufferCommands":true,"stateLogEnabled":false,"queueLogEnabled":false,"tcpHost":"192.168.1.51","tcpPort":"502","tcpType":"DEFAULT","serialPort":"/dev/ttyUSB","serialType":"RTU-BUFFERD","serialBaudrate":"9600","serialDatabits":"8","serialStopbits":"1","serialParity":"none","serialConnectionDelay":"100","unit_id":"1","commandDelay":"1","clientTimeout":"2000","reconnectOnTimeout":true,"reconnectTimeout":"4000","parallelUnitIdsAllowed":true}]
```
---
### Author:  [@UnborN](https://discourse.nodered.org/u/UnborN)
#### Post date: [1 October 2021 18:30 UTC](https://discourse.nodered.org/t/read-registers-from-modbus-not-in-sequence/51710/14 "2021-10-01T18:30:03Z")
I'm posting a part of my flow also, that i use to read in sequence a bunch of Energy Meters using Modbus serial. Hope you find something useful in it.
The steps used.
1. use Cron-plus node to trigger the sequence of reads.
2. use an "error" function to fill with null values for any device that may be offline
3. join the results after passing them from buffer-parser.
4. save them in Context
[ModbusFlow.json](https://discourse.nodered.org/uploads/short-url/aH41MtRWqHGUaXYpEPMGANjPSw0.json) (54.1 KB)
---
### Author:  [@Colin](https://discourse.nodered.org/u/Colin)
#### Post date: [1 October 2021 19:56 UTC](https://discourse.nodered.org/t/read-registers-from-modbus-not-in-sequence/51710/15 "2021-10-01T19:56:54Z")
I think I would probably have parsed each buffer before moving on the next modbus node, then it would be trivial to combine them .
---
### Author:  [@PLCMercenary](https://discourse.nodered.org/u/PLCMercenary)
#### Post date: [2 October 2021 03:11 UTC](https://discourse.nodered.org/t/read-registers-from-modbus-not-in-sequence/51710/16 "2021-10-02T03:11:44Z")
@UnborN, I just let throw them at the flex getter and it handles them.. Its not a massive amount of tags, 70 - 90 for the main PLC status and alarms. most have 1, 2 or 3, VFDs I also read 10 or 12 tags each the same way.. relevant snippets are below...
```auto
[{"id":"73599554.0351dc","type":"function","z":"64187f31.4b904","name":"cacheConfig","func":"//varpts=msg.payloadvarpoints_lookup={}pts.forEach(function(p){if(points_lookup[p.reg_name]){points_lookup[p.reg_name].points.push({'bit':parseInt(p.bit),'name':p.point_name,'alias_on':p.alias_on,'alias_off':p.alias_off,'parse':p.parse})}else{points_lookup[p.reg_name]={}points_lookup[p.reg_name].name=p.reg_namepoints_lookup[p.reg_name].parse=p.parsepoints_lookup[p.reg_name].group=p.grouppoints_lookup[p.reg_name].quantity=p.quantitypoints_lookup[p.reg_name].address=parseInt(p.reg_address)points_lookup[p.reg_name].points=[]points_lookup[p.reg_name].points.push({'bit':parseInt(p.bit),'name':p.point_name,'alias_on':p.alias_on,'alias_off':p.alias_off})}});flow.set('points',points_lookup)\nvar pts = msg.payload\nvar points_lookup = {}\npts.forEach(function(p){\n \n if (points_lookup[p.reg_name]) {\n points_lookup[p.reg_name].points.push({'bit': parseInt(p.bit), 'name': p.point_name, 'alias_on': p.alias_on, 'alias_off': p.alias_off, 'parse': p.parse})\n } else {\n points_lookup[p.reg_name] = {}\n points_lookup[p.reg_name].name = p.reg_name\n points_lookup[p.reg_name].parse = p.parse\n points_lookup[p.reg_name].group = p.group\n points_lookup[p.reg_name].quantity = p.quantity\n points_lookup[p.reg_name].address = parseInt(p.reg_address)\n points_lookup[p.reg_name].points = []\n points_lookup[p.reg_name].points.push({'bit': parseInt(p.bit), 'name': p.point_name, 'alias_on': p.alias_on, 'alias_off': p.alias_off})\n } \n});\n\nflow.set('points', points_lookup) ","outputs":1,"noerr":0,"initialize":"","finalize":"","libs":[],"x":690,"y":220,"wires":[[]]},{"id":"2aa1c606.326e2a","type":"file in","z":"64187f31.4b904","name":"","filename":"/data/modbus_points.csv","format":"utf8","chunk":false,"sendError":false,"encoding":"none","x":270,"y":220,"wires":[["3d104107.371ece"]]},{"id":"3d104107.371ece","type":"fastcsv","z":"64187f31.4b904","name":"fastcsv","headers":true,"headerstr":"","ignoreEmpty":true,"discardUnmappedColumns":true,"strictColumnHandling":false,"delimiter":",","quote":"\"","escape":"\"","comment":"#","ltrim":false,"rtrim":false,"rowDelimiter":"\\n","includeEndRowDelimiter":false,"quoteHeaders":false,"quoteColumns":false,"x":480,"y":220,"wires":[["73599554.0351dc"]]},{"id":"7e742181.e1e8b","type":"function","z":"64187f31.4b904","name":"LoopThroughPoints","func":"var points = flow.get('points')\nvar modbusStatus = flow.get('modbusStatus')\nif(points && (modbusStatus.indexOf('active') != -1 || modbusStatus.indexOf('timeout') != -1 )) {\nvar numPoints = Object.keys(points).length\nvar idx = flow.get('idx')\nif (idx == undefined || idx >= numPoints) {\n idx = 0\n}\n\nvar names = Object.keys(points)\nmsg.points = points[names[idx]].points\nmsg.name = names[idx]\nmsg.parse = points[names[idx]].parse\nmsg.group = points[names[idx]].group\n//node.error(msg.name)\nmsg.payload = { value: msg.payload, 'fc': 3, 'unitid': 1, 'address': points[names[idx]].address, 'quantity': points[names[idx]].quantity }\n\nif(idx <= numPoints-1) {\n idx += 1\n flow.set('idx', idx)\n \n} else {\nflow.set('idx', 0) \n}\nreturn msg; \n}\n\n","outputs":1,"noerr":0,"initialize":"","finalize":"","libs":[],"x":690,"y":320,"wires":[["acc10367.8945c"]]},{"id":"ba625744.8c9338","type":"function","z":"64187f31.4b904","name":"ParseResult","func":"//if(msg.name==\"Status\"){returnmsg}elseif(msg.name.indexOf(\"Alarms\")!=-1){return[null,msg]}else{return[null,null,msg]}\n\nif (msg.name == \"Status\") {\n return msg\n} else if(msg.name == \"Alarms\") {\nreturn [null,msg] \n} else {\nreturn [null,null,msg]\n}\n\n","outputs":3,"noerr":0,"initialize":"","finalize":"","libs":[],"x":1160,"y":320,"wires":[[],[],[]]},{"id":"1244d16a.3f7adf","type":"inject","z":"64187f31.4b904","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"3","crontab":"","once":false,"onceDelay":0.1,"topic":"","payloadType":"date","x":240,"y":320,"wires":[["6db508f3.149ba8"]]},{"id":"6db508f3.149ba8","type":"moment","z":"64187f31.4b904","name":"InjecttimeStamp","topic":"","input":"","inputType":"date","inTz":"America/Chicago","adjAmount":0,"adjType":"days","adjDir":"add","format":"MM/DD/YYhh:mmA","locale":"POSIX","output":"timeStamp","outputType":"msg","outTz":"America/Chicago","x":450,"y":320,"wires":[["7e742181.e1e8b"]]},{"id":"acc10367.8945c","type":"modbus-flex-getter","z":"64187f31.4b904","name":"","showStatusActivities":false,"showErrors":false,"logIOActivities":false,"server":"","useIOFile":false,"ioFile":"","useIOForPayload":false,"emptyMsgOnFail":false,"keepMsgProperties":true,"x":930,"y":320,"wires":[["ba625744.8c9338"],[]]}]
```
---
### Author:  [@system](https://discourse.nodered.org/u/system)
#### Post date: [1 December 2021 03:12 UTC](https://discourse.nodered.org/t/read-registers-from-modbus-not-in-sequence/51710/17 "2021-12-01T03:12:40Z")
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