Siemens 611-D, 840C 12.28.5 Configuration of a high-speed data channel, 12.28.6 Fast synchronous data channel

12 Functional Descriptions 07.97

12.28.5 Configuration of a high-speed data channel

12.28.5 Configuration of a high-speed data channel

Step 1: Reset activation signal in DB 3.

Step 2: Divide up DB 3 appropriately for all data transfer areas used. Program pointers for

the data transfer areas accordingly.

Step 3: Enter job number in configuring channel, enter number of data transfer area, enter

function identifier and configuring parameters, set bits for read/write operations and

acknowledgement bit if appropriate. Set strobe.

Step 4: Wait for NC to reset strobe.

Step 5: Evaluate any error message from NC.

Step 6: If no error message is output, the high-speed data channel can now be activated

(enter value to be written, if any, beforehand).

12.28.6 Fast synchronous data channel

With the function ”Synchronous data channel” it is possible to access several NCK data

(access via several ”fast data channels”) ”simultaneously” (i.e. all data refer to one IPO

cycle). Synchronous data channels are always operated ”with acknowledgment”, irrespective

of their configuration (DB 2 DL 0 bit 7).

The way the data channel is configured has not changed. The activation bits (DB 3 DW 0-1)

must be set.

Setting the data-channel-specific bit ”Synchronous data channel” (DB 3, DRx, bit 2) makes the

data channel a ”synchronous data channel”. The data channel is then no longer controlled via

the data-channel-specific bits ”New values, read NC data” and ”New values, write NC data”

(DB3, DRx, bit 0 and bit1) but via the synchronous data channel bits ”New values, read NC

data” and ”New values, write NC data” (DB3, DR12, bit 0 and bit 1). As all the synchronous

data channels are controlled by these bits, all data channels are activated simultaneously.

With a synchronous ”Read NC data” the PLC requests the data from the NCK by resetting bit

”New values, read NC data” (DB3, DR12, bit 0). Once the NCK has read all data it signals this

to the PLC by setting this bit.

With a synchronous ”Write NC data” the PLC initiates writing by setting bit ”New values,

write NC data” (DB3, DR12, bit 1). Once the NCK has written all data this is signaled to the

PLC by resetting this bit.

Notes:

• The function ”Synchronous data channel” is only available for function identifiers 02

(digital I/O in NCK) and 03 (NCK data). With function identifier 01 (drive data and servo

data) bit ”Synchronous data channel” is ignored.

• Synchronous data channels can be converted to ”normal” data channels at any time by

resetting bit ”Synchronous data channel”. They are then operated with or without

acknowledgment depending on the configuration.

• The data-channel-specific bits ”New values, read NC data” and ”New values, write NC

data” (DB3, DRx, bit 0 and bit 1) are not processed by the NC when synchronous data

channels are set (i.e. the status of these bits is irrelevant).

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SINUMERIK 840C (IA)