I/O modules • 237
Incremental-encoder-interface 750-631
cumulation register depending upon the status of the overflow or underflow bits.
Setting Counter Position:
The counter can be preset with the CNT_SET bit.
The desired preset is loaded into the data register and the CNT_SET bit is set from 0 to 1. The CNTSET_ACC bit will be set to 1 when the preset value is loaded into the count register.
Maintaining the Present Counter Position:
The encoder present value may be maintained or latched via the external Latch input. First the external latch must be enabled via the EN_LATEXT bit. Once the input is enabled, the data will be latched into the counter module upon a 0 to 1 transition. Upon completion of the latch process the external latch valid bit LATEXT_VAL will be set to 1.
Maintaining a Reference Point:
The storage of a present counter value may also accomplished via the Index pulse from the encoder. First the index latch enable bit must be set, EN_LACT, to a value 1. The encoder present value will be latched upon the low to high transition of the Index input. Upon completion of the data latch process the Index Latch Valid bit, LACT_VAL will be set to 1.
Attention
For the process data configuration of these bus modules please refer to chapter "Process data architecture for MODBUS/TCP" in the process image description of the corresponding coupler/controller.
Modular I/O System
ETHERNET TCP/IP
can be used. A cable with a 9- pole sub-D socket is required. Pin 5 is connected to input "common". Pin 2 is connected to TxD and Pin 3 to RxD. RTS and CTS of the module are connected. A hardwarehandshake between the terminal emulation and the PLC is not possible.