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WAV Write Remote Analog Value Function Block
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Write Remote Analog value (WAV) function blocks allow any analog value to be transmitted to other devices on the network in a peer-to-peer fashion. Values can be transmitted with the MBus_ioFlash protocol or with the Modbus protocol. Adding WAV blocks to a device will make that device behave as a Modbus Master on the RS485 network it is connected to. You can add several WAV blocks in combination with WDV and SCAN blocks on the same device, communications will be managed automatically so there are no collisions.
** Important note: on an RS485 network there can only be one master device, otherwise communications from one master would collide with the other. Therefore you must make sure that the WAV blocks are only used an a device that will be designated as Master the RS485 network it is connected to. You should deactivated the block (see Scan On parameter below) before attempting remote communications from MBus_ioFlash or any other Modbus Master on the RS485 network.
| Parameter | Description |
| Name | Function block name, see common parameters |
| Units | Parameter's engineering units, see common parameters |
| Scale | Parameter's scale, see common parameters |
| Format | Parameter's format, see common parameters |
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DYN dynamic option, see common parameters |
| Input | This is the input parameter that the block will transmit to remote devices. The value is monitored and if it changes the new value is transmitted to the remote device. |
| Scan On | Digital input to control whether the WAV block is active or not. See note above. |
| Rate | Determines the maximum rate that new values will be transmitted. If the input value is constantly changing this this parameter can be used to limit the amount of data transmitted on the RS485 network. |
| Threshold | The amount of change required to trigger a retransmission to
the remote device. For example if set to 1, the input parameter must
change by more that 1 unit to trigger a retransmission. If set to 0.0 any
change in the input parameter will trigger a retransmission, however
if there is no change no transition will occur.
Note that whenever the device is restarted at least one transition will be forced to make sure the remote value is initialized. |
| Network Parameter: MBus_ioFlash / Modbus | Determines the protocol to use to transmit the value to the remote device. If Modbus is selected the the Modbus command "(0x06) Write Single Register" is used. Since this command requires the value to be represented as a 16 bit integer the decimal point format of the block will be used to convert the value. |
| Network Parameter: Dev addr | Modbus address of the device on the RS485 network that receive the analog value. |
| (MBus_ioFlash protocol selected)
Network Parameter: Block name |
The name of the analog block within the target device's MBus_ioFlash program. |
| (Modbus protocol selected)
Network Parameter: Reg No. |
The Modbus register number within the target device's register space. Note that base(1) numbering is assumed. |
