How to simply write/read signed and unsigned values

[Toni16]

Hello

I have a ventilation system which is using RTU modbus to communicate.
Some of values are signed and others unsigned.
I can read unsigned values, default config of Modbus-contrib. I am not sure that it's working properly for signed values since it's the outside temperature and actually it is positive.
How to parameter the node to read signed values?

Tx

Antoine

[Steve-Mcl]

There is a contrib designed for simplifying this. It contains a parser and maker node.

node-red-contrib-buffer-parser

[{"id":"f5410105eecb8283","type":"inject","z":"85e1791bc0cd6285","name":"write 16001.5","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"16001.5","payloadType":"num","x":1020,"y":440,"wires":[["f958f283b7aadc13"]]},{"id":"bc8160dfb8d6553a","type":"buffer-parser","z":"85e1791bc0cd6285","name":"","data":"payload","dataType":"msg","specification":"spec","specificationType":"ui","items":[{"type":"uint16be","name":"item1","offset":0,"length":-1,"offsetbit":0,"scale":"1","mask":""}],"swap1":"","swap2":"","swap3":"","swap1Type":"swap","swap2Type":"swap","swap3Type":"swap","msgProperty":"payload","msgPropertyType":"str","resultType":"value","resultTypeType":"return","multipleResult":false,"fanOutMultipleResult":false,"setTopic":true,"outputs":1,"x":1410,"y":440,"wires":[["597e975260b85355"]]},{"id":"597e975260b85355","type":"debug","z":"85e1791bc0cd6285","name":"","active":true,"tosidebar":true,"console":false,"tostatus":true,"complete":"payload[0]","targetType":"msg","statusVal":"payload","statusType":"auto","x":1400,"y":500,"wires":[]},{"id":"f958f283b7aadc13","type":"buffer-maker","z":"85e1791bc0cd6285","name":"","specification":"spec","specificationType":"ui","items":[{"name":"item1","type":"floatbe","length":1,"dataType":"msg","data":"payload"}],"swap1":"","swap2":"","swap3":"","swap1Type":"swap","swap2Type":"swap","swap3Type":"swap","msgProperty":"payload","msgPropertyType":"str","x":1220,"y":440,"wires":[["bc8160dfb8d6553a"]]}]