Before you can enroll a Modbus device in your system, you must enable the Modbus Client protocol on the Industrial IoT plugin role.
Procedure
-
In the Modbus Client section to the right, configure the following
settings and click Apply.
- Data polling interval
- The period (in milliseconds) at which Security Center polls the device. The default value
is 1000 milliseconds.NOTE: The optimal polling interval depends on your application and the number of inputs. An industrial application, such as monitoring the temperature of a volatile compound, requires smaller interval. Monitoring office building temperatures requires less frequent monitoring.
Shorter polling intervals, more rules, and more inputs increase CPU demand. These settings are limited by the processing power of the computer that hosts the plugin.
- Timeout
- The time (in milliseconds) given to a device to respond to a request sent out by the Industrial IoT plugin role. The default is 1000 milliseconds. If you get a lot of expired requests, increase this number.
- Address format
- The address format used in the user interface of the plugin. Choose either Decimal or Hexadecimal.
- Optimize read requests
- When this option is enabled, you can set a read request to poll multiple
properties on a Modbus device. For example, if you have a device with 100 coils,
instead of making 100 requests that read one coil each, you can make one request to
read 100 coils.
- Coil / discrete inputs per read
- Number of coils or discrete inputs you want to poll with each request. The maximum is 2000.
- Holding / input registers per read
- Number of holding or input registers you want to poll with each request. The maximum is 125
Note that only adjacent registers can be read together.
