modbus.connect()
modbus.connect(host, port, unitId) → numberOpens a Modbus TCP connection to a remote device.
Arguments
| Name | Type | Required | Default | Description |
|---|---|---|---|---|
| host | string | yes | — | IP address of the Modbus device, e.g. "172.16.220.111". |
| port | number | yes | — | TCP port, normally 502. |
| unitId | number | yes | — | Slave unit ID. |
Returns
number
0 on success, otherwise an error code.
Example
let ret = modbus.connect("172.16.220.111", 502, 1);
if(ret === 0){
// read / write ...
modbus.disconnect();
} else {
print("Modbus Connect Failed, err=", ret);
}