Modbus Coil Receiver

Operator Menu Location: Generic Hardware Operators Networking Modbus

Operator Bitmap:

Functional Description:
The Modbus Coil Receiver generic hardware operator provides access to a networking channel resource in the physical hardware. When the generic operator is linked to a specific networking hardware resource, it will receive messages broadcast over that channel resource using the Modbus protocol.

The Modbus Coil Receiver operator decodes Modbus messages broadcasted over a network. The operator has three outputs:
•Digital output is the value of the broadcast signal obtained from the network.
•Digital output indicates if the value has changed since the last transmission. The output is HIGH during the single schema compute cycle in which the signal value change was detected; otherwise it is LOW.

•Digital output b indicates if the broadcast transmissions are being received regularly (i.e., indicates if the network link is good). It is LOW while transmissions are regularly received, and the output is HIGH if the operator has not received a broadcast in a user-specified time interval (the Broadcast Dead-Time property of the receiver).

In order to associate a receiver operator to a particular network broadcast, the generic operator must be linked to a specific network channel in the physical hardware, and its signal name property must match the broadcast signal name exactly. Signal names are case sensitive---Design Pad considers the names "OilPressureAlarm", "oilPressureaLarm", and "OILPRESSUREALARM" to refer to different signals.

User-Defined Properties:
Signal Name. A string label that identifies the broadcast signal that the receiver is "tuned" to. Design Pad associates this receiver operator in one schema with a broadcast operator in another schema that has the same signal name.

Maximum Broadcast Dead-Time. The period of time (in milliseconds) that may elapse before the receiver operator indicates that it has not received a broadcast signal (switches output to HIGH). Output remains LOW while the operator actively receives the broadcasted signal.
Display Value Change of Value Output. This property determines if the error output pin is visible in the schema diagram. Design Pad issues a warning upon processing the schema when the pin is visible but not connected. The warning message is not issued when the pin is not visible (when this property is not checked).
Display Error Output. This property determines if the error output pin is visible in the schema diagram. Design Pad issues a warning upon processing the schema when the pin is visible but not connected. The warning message is not issued when the pin is not visible (when this property is not checked).

Comments: None.

See Also:
Modbus Coil Broadcast, Modbus Register Receiver, Modbus Register Broadcast