KNOT MQTT Modbus Messaging

RouterOS Scripting
1

I have modbus on the KNOT working with this example code…

{:local output [/iot modbus read-holding-registers slave-id=1 reg-addr=1 num-regs=2 as-value once];:put [($output->"values")]}

And MQTT working with example code…

# Required packages: iot

################################ Configuration ################################
# Name of an existing MQTT broker that should be used for publishing
:local broker "AWS"

# MQTT topic where the message should be published
:local topic "my/test/topic"

#################################### System ###################################
:put ("[*] Gathering system info...")
:local cpuLoad [/system resource get cpu-load]
:local freeMemory [/system resource get free-memory]
:local usedMemory ([/system resource get total-memory] - $freeMemory)
:local rosVersion [/system package get value-name=version \
    [/system package find where name ~ "^routeros"]]
:local model [/system routerboard get value-name=model]
:local serialNumber [/system routerboard get value-name=serial-number]
:local upTime [/system resource get uptime]

#################################### MQTT #####################################
:local message \
    "{\"model\":\"$model\",\
                \"sn\":\"$serialNumber\",\
                \"ros\":\"$rosVersion\",\
                \"cpu\":$cpuLoad,\
                \"umem\":$usedMemory,\
                \"fmem\":$freeMemory,\
                \"uptime\":\"$upTime\"}"

:log info "$message";
:put ("[*] Total message size: $[:len $message] bytes")
:put ("[*] Sending message to MQTT broker...")
/iot mqtt publish broker=$broker topic=$topic message=$message
:put ("[*] Done")

Now I am trying to combine the two…

# Required packages: iot

################################ Configuration ################################
# Name of an existing MQTT broker that should be used for publishing
:local broker "AWS"

# MQTT topic where the message should be published
:local topic "my/test/topic"

#################################### System ###################################
:put ("[*] Gathering system info...")
:local cpuLoad [/system resource get cpu-load]
:local freeMemory [/system resource get free-memory]
:local usedMemory ([/system resource get total-memory] - $freeMemory)
:local rosVersion [/system package get value-name=version \
    [/system package find where name ~ "^routeros"]]
:local model [/system routerboard get value-name=model]
:local serialNumber [/system routerboard get value-name=serial-number]
:local upTime [/system resource get uptime]

:local voltage [/iot modbus read-holding-registers slave-id=1 reg-addr=1 num-regs=2 as-value once]

#################################### MQTT #####################################
:local message \
    "{\"model\":\"$model\",\
                \"sn\":\"$serialNumber\",\
                \"ros\":\"$rosVersion\",\
                \"cpu\":$cpuLoad,\
                \"umem\":$usedMemory,\
                \"fmem\":$freeMemory,\
                \"uptime\":\"$upTime\",\
                \"volatge\":\"$voltage\"}"

:log info "$message";
:put ("[*] Total message size: $[:len $message] bytes")
:put ("[*] Sending message to MQTT broker...")
/iot mqtt publish broker=$broker topic=$topic message=$message
:put ("[*] Done")

Assume i’ve gone wrong somewhere here?

:local voltage [/iot modbus read-holding-registers slave-id=1 reg-addr=1 num-regs=2 as-value once]

Any assistance appreciated.

2

It would look something like this:

:local modbusread [/iot modbus read-holding-registers slave-id=0x03 num-regs=0x1 reg-addr=0x0 as-value once]
:local modbus [:put [($modbusread->“values”)]]

#################################### MQTT #####################################
:local message
“{"AnalogOutputHoldingRegister":"$modbus"}”

3

Using the script of Modbus to MQTT, how can I get the results of 20 meters (address 1 to 20) and have this run every 30 seconds

4

Create different variables for each address and set up the scheduler (to run the script whenever you like).