Delta AH500 - Page 589

Chapter 6 Applied Instruction
6-421
8. If the communication timeout occurs, SM104 and SM105 are ON, and SM98 and SM99 are
OFF.
9. If the error occurs during the reception of the data, SM102 and SM103 are ON, and SM98 and
SM99 are OFF.
10. If the function code specified by S
2
is related to the word device, the device in the external
equipment with which the AH500 series PLC communicates has to be the word device. If the
function code specified by S
2
is related to the bit device, the device in the external equipment
with which the AH500 series PLC communicates has to be the bit device.
11. The flags related to the instruction MODRW:
Flag
Description
COM1
COM2
SM96
SM97
The data is sent through COM1/COM2.
SM98 SM99
Waiting to receive the reply through
COM1/COM2
SM100 SM101
Reception through COM1/COM2 is
complete.
SM102 SM103
An error occurs during the reception of the
data through COM1/COM2
SM104 SM105
No data is received through COM1/COM2
after a specified period of time.
SM209 SM211
The communication protocol of COM1
changes (in accordance with SM210,
SR201, SR209, and SR215).
Please refer to the explanation of the instruction RS for more information about the functions of
the flags.