Omron NB3Q-TW00B Startup Manual Manual page 116

6 Maintenance and Troubleshooting
6
How to decide whether communications are normal or not through the internal addresses of the PT
Decide Deciding which PLC is disconnected with through a bit;
Serial port 2: LW9432-9447, 16 words are equivalent to 256 bits, with each bit corresponding to
a PLC. No response = ON, Normal = OFF.
See the following diagram:
Assume that 3 S7-200 PLCs connect to the COM2 port of NB7W, the station numbers of which
are 2, 3, 4 respectively; if the PLCs with the station numbers 2 and 4 fail communication, the
internal registers LW.B9432.2 and LW.B9432.4 will turn ON automatically, as shown below:
7
The communications of the PT and PLC are normal, but why are some numeric values are
indicated as "****"
When the data coming from registers communicating with the PLC exceeds the setting range of
the Number Display or Number Input, "****" will appear. It indicates an overflow of a numeric
value. The user can set the integer bit digit number range of the Number Display or Number
Input larger through NB-Designer to make numeric value display normal. For example, change
the integer bit digit number from 3 to 4.
6-28 NB-series Programmable Terminals Startup Guide Manual(V109)