Rockwell Automation 1771-DA,D17716.5.13 U MNL 1771-DA ASCII I/O MODULE - Manual (Page 158)

Function of Control/Status Bits
Chapter 6
6Ć23
Status Word One
Bit Function Status*
17 Channel Active 0 = Reset
1 = The ASCII device is enabled
16 Write Data
Acknowledge
Module toggles SW1(16)=CW1(16) to tell
PC that new data was received
15 Read Data Available Module toggles SW1(15) ≠ CW1(15) when
it detects a change in status or receives
new data from ASCII device
14 Input String Exceeds
Maximum
0 = Reset
1 = Input string >set string length in
IW2(00Ć13)
13 ASCII Device/Link
Error
0 = Reset
1 = Module detects parity, framing or
overrun error in string from the ASCII
device
12 Initialization Error 0 = Reset
1 = Module ceases to operate
11 Not Used Module sets it to zero
10 Data Complete 0 = Reset
1 = Module detects delimiter at end of
string that is distributed over one or
more block transfers.
07 PowerĆup
Initialization
0 = Reset by CW1(07)
1 = PowerĆup initialization is complete
06 Not used Module sets it to zero
05 Output Buffer Full 0 = Reset when less than full
1 = Output buffer full
04 Output Buffer Empty 0 = Reset when data enters buffer
1 = Output buffer empty
03 Input Buffer full 0 = Reset by CW1(03) when input buffer is
empty
1 = Input buffer is full
02 Input Buffer 75% Full 0 = Reset when less than 75% full
1 = Input buffer is 75% full
01 Input Buffer 50% Full 0 = Reset when less than 50% full
1 = Input buffer is 50% full
00 Input Buffer Empty 0 = Reset when data enters buffer
1 = Input buffer is empty
*The module sets these bits (unless toggled) when it detects the subject condition.