ACS_COM_MOD_RTU_GEN Communication for Generic Devices via MODBUS RTUΒΆ
Function Block ACS_COM_MOD_RTU_GEN controls the MODBUS RTU communication to a generic slave device. It must be used together with the Function Blocks ACS_COM_MOD_RTU_GEN_READ_N_PRM and/or ACS_COM_MOD_RTU_GEN_WRITE_N_PRM to exchange MODBUS data.
Block Data
| Available as of PLC runtime system: | V1.3.2 |
| Included in library: | ACSDrivesComModRTU_AC500_V20.lib |
| Function Block | with historical values |
Function Bock ACS_COM_MOD_RTU_GEN_READ_N_PRM reads n data of the slave device. The number of data to be read is specified at the input NB. The first address is specified at the input ADDR. The values of the data is stored in the PLC memory area, defined at the input DATA. The values in the PLC memory area are updated when the read job was performed without error. This is indicated by DONE = TRUE and ERR = FALSE.
As long as the EN = TRUE a new read job is requested each time the further read job is terminated.
The MODBUS job is started from the ACS_COM_MOD_RTU_GEN Function Block which is connected to the same SLAVE_DATA variable.
The slave address of the device from which the data is read is specified at this ACS_COM_MOD_RTU_GEN block.
If the input values are valid, a request to perform a MODBUS RTU job is send to the ACS_COM_MOD_RTU_GEN block via the SLAVE_DATA variable.
If at least 1 input is invalid, no job is generated and the error is displayed at the outputs ERR and ERNO instead.
Note
The ACS_COM_MOD_RTU_GEN_READ_N_PRM Function Block does only change the values at the DATA input if the MODBUS job was excecuted without errors. If the block is not enabled or the connection to the ACS_COM_MOD_RTU_GEN block is not ok these values are not updated and keep their previous values. This is also the case for the internal VALUE array. However the ACS_MOD_READ_N_PRM for drives does reset its values attached to DATA input and the VALUE array to zero in case of no connection to the related ACS_COM_MOD Function Block or if the block is not enabled.