
1.16/18/21-B, 16/18-C, LCD-MOUNTED TYPE 16i/18i/21i-A/B OPERATION B-62714EN/04
- 40 -
Communication status for ladder detection of the slave function
Communication status allocation (when DI/DO MAP MODE = 0 [DI/DO data
transfer])
[STATUS ADDRESS] Status of communication with the
master station
Communication status allocation (when DI/DO MAP MODE = 2 [global I/O
transfer])
[STATUS ADDRESS] Status of communication with the
master station
+1 Status of communication with
slave station #1
+2 Status of communication with
slave station #2
+3 Status of communication with
slave station #3
::
+[STATION NO]
(This area corresponds to the
local slave station, and is not
used. This area cannot be used
for other purposes.)
::
+[MAX SLAVE NO] Status of communication with
slave station #[MAX SLAVE NO]
Status of communication with the master station
Status of communication with the master station (1 byte):
The status of communication with the master station is indicated.
bit 7bit 6bit 5bit 4bit 3bit 2bit 1bit 0
Bit 7 : LINK STATUS (status of the link with the master station)
- When LINK STATUS = 0, the link is disconnected.
- When LINK STATUS = 1, communication is performed
normally.
Bit 6 : Short frame error
Bit 5 : Abort detection
Bit 4 : Detection of data consisting of an incorrect number of bits
Bit 3 : Overrun error detection
Bit 2 : FCS error detection
Bits 1, 0 : Reserved (0 at all times)
NOTE
Many errors are caused by hardware failures (on
communication boards or communication cables)
and noise. Recheck the method of communication
cable connection, terminating resistor, and noise
protection.