Rockwell Automation 1770-KF2 Data Highway or Highway Plus Interface Module User Manual User Manual

Page 99

Message Packet Formats

Chapter 5

5-20

Set Variables

This command is a combination of the above three commands. It sets the
maximum ENQs, NAKs, and timeouts all at once. Put the timeout setting
in the first byte of the DATA field, the NAKs setting in the second byte,
and the ENQs in the third byte.

Command Format:

Reply Format:

TNS

STS

CMD

SRC

DST

TNS

STS

CMD

SRC

DST

FNC

DATA — 3 Bytes

Timeouts

NAKs

ENQs

Unprotected Bit Write

This command sets or resets individual bits in any area of PC data table
memory.

The data field in this packet consists of 4-byte blocks, each of which
contains a 16-bit address field, a set mask, and a reset mask. Use the
ADDR field to specify the address of the byte to be modified in the PC
data table memory. Put the low byte (least significant bits) of the PC
address value into the first byte of the ADDR field. Refer to Chapter 6 for
more details on how to specify an address value.

Use the SET mask to specify which bits to set to 1 in the addressed PC
byte. A 1 in a bit position of the SET mask means to set the
corresponding bit in the addressed PC byte to 1; a 0 in a bit position of the
SET mask means to leave the corresponding bit in the PC byte
unchanged.

Use the RESET mask to specify which bits to reset to 0 in the addressed
PC byte. A 1 in a bit position of the RESET mask means to reset the
corresponding bit in the addressed PC byte to 0; a 0 in a bit position of the
RESET mask means to leave the corresponding bit in the PC byte
unchanged.