Modbus Register Broadcast

Operator Menu Location: Generic Hardware Operators

Networking

Modbus

Operator Bitmap:

Functional Description:
The Modbus Register Broadcast 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 broadcast a message over that channel resource using the Modbus protocol.

Modbus Register Broadcast operators encode their input signal x into a communication message that they broadcast over an industrial network. All devices connected to the network will receive the broadcasted message. But, only those controllers with a receiver operator "tuned" to that broadcast will actually decode the message.

The Modbus Register Broadcast operator has two inputs---one analog and one digital. Analog input x is the signal that the operator is to broadcast. Digital input b disables (HIGH) or enables broadcasting (LOW). If the digital input is not connected, broadcasting is always enabled.

The operator transmits 16-bit messages that can represent: a floating-point value, an unsigned integer value in the range
[0,65535
], or a signed integer value in the range
[-32768,32767
].
When configured to transmit a floating-point value, the operator maps input x into a 16-bit representation: transmits is determined from:

where

is the minimum value that x is expected to assume and

is the maximum value that x is expected to assume. The signal mappings

and

are properties of the operator. The narrower the band defined by

and

the better resolution the broadcasted message retains.
When configured to transmit an unsigned integer value, the operator first rounds input x to the nearest integer, then broadcasts the value. If the input is outside of the unsigned integer range, the value is clipped. In other words the broadcast message, m is

Similarly, when configured to transmit a signed integer value, the broadcast message is

User-Defined Properties:
Signal Name. A string label that identifies the broadcast signal. It is used to associate this Modbus Register Broadcast operator in one schema with Modbus Register Receiver operator(s) in other schemas.

Initial Broadcast Value. The signal value transmitted initially.

Network Data Format. Determines the format of the transmitted message: Analog Range, Unsigned Integer, or Signed Integer. The Analog Range setting is used to transmit floating-point values, according to the mapping formula above.
0% Mapping. The lower limit of the x input signal range,

100% Mapping. The upper limit of the x input signal range,

.

Display Disable Input. This property determines if the disable input pin b 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 Register Receiver, Modbus Coil Broadcast, Modbus Coil Receiver