Input DescriptionΒΆ
Note
The inputs marked with a triangle 
are of the class VAR_IN_OUT (input and output variable). These inputs must be connected to a variable.
EN (enable)
Data type: BOOL
In order to enable the Function Block processing, input EN has to be continuously set to TRUE. The Function Block is not processed, if input EN = FALSE. When calling the Function Block the first time, the inputs are checked for validity and plausibility. If this is not the case, processing is aborted and corresponding error is displayed at output ERR/ERNO.
PRIO (priority)
Data type: BOOL
Input PRIO is reserved for future usage. It can be left open.
FCT (number of variables)
Data type: BYTE
The function code of the request telegram is specified at input FCT.
| 01 or 02 | read n bits |
| 03 or 04 | read n words |
| 05 | write one bit |
| 06 | write one word |
| 15 | write n bits |
| 16 | write n words |
NB (number of variables)
Data type: UINT
At input NB, the number of data to be read is specified.
The unit of NB depends on the selected function. For bit accesses the number of bits, for word and double word accesses the number of words is specified at NB.
Default: 1. Minimum 1, Maximum 96.
ADDR (address)
Data type: UINT
The operand/register address in the slave from which data should be read is specified at input ADDR.
The access to operands of AC500 devices in MODBUS slave mode is defined via the MODBUS cross-reference list. Only operands that are listed in the cross-reference list may be used (see Communication with MODBUS RTU).
Only operands that are listed in the MODBUS address list may be used. When accessing other devices, ADDR is freely selectable. The valid ranges have to be gathered from the corresponding device description.
DATA (data)
Data type: DWORD
At input DATA, the address of the first operand in the PLC is specified to which the data read by the slave should be stored.
For this purpose it is necessary that all PLC variables, which are written to the drive, have consecutive addresses. This can be obtained by declaration of each variable within the %MW0.xxx area or declaration of an array containing all variables.
Declaration of each variable has the advantage, that the types (integer or word) can be selected individually.
SLAVE_DATA (slave data)
Data type: ACS_DRIVE_DATA_TYPE
The combined input/output SLAVE_DATA must be connected to the variable of type ACS_GEN_DEV_DATA_TYPE of the related slave device. Each device must have its own SLAVE_DATA variable.
The SLAVE_DATA variable transfers the MODBUS data from the ACS_COM_MOD_RTU_GEN_READ_N_PRM or ACS_COM_MOD_RTU_GEN_WRITE_N_PRM Function Blocks to the ACS_COM_MOD_RTU_GEN function block. It contains also some information about the online state of the device and must be connected to all related Function Blocks of this device.