Modbus RTU:making request without "parameter descriptor" setup

[davdav]

Hi everybody,

I would like to use freemodbus component to implement a modbus MASTER.

I have two concerns using the component:
1. The serial port which will send the modbus request (UART0) is currently used, so its driver is installed and a specific task manages its event: suspending the task it's OK but should I also delete the driver every time I want to send a modbus request?

2. since modbus request will be made "on-the-fly" (no knowledge of what function code and/or register number is requested), is it possible to avoid the setup of the "parameter descriptor" as reported in the example:
is is possible to use only "mbc_master_send_request" API to read/write the modbus slave register?


Thanks

[ESP_alisitsyn]

Hi davdav,

since modbus request will be made "on-the-fly" (no knowledge of what function code and/or register number is requested), is it possible to avoid the setup of the "parameter descriptor" as reported in the example:
is is possible to use only "mbc_master_send_request" API to read/write the modbus slave register?

The modbus master implementation uses modbus controller interface layer above modbus to use modbus with other implementations like MDF. You can use the modbus API and mbc_master_send_request() in your application if absolutely required. See the file mbc_serial_master.c/h of modbus controller as an example of using the modbus port layer.