DeltaV Diagnostics view showing port statistics.This technical note describes the integration of Wago 750-841 IO to DeltaV using Modbus TCP/IP and the Virtual IO Module.
The purpose of this application note is to document the testing of a Modbus TCP/IP device, Wago 750-851 Controller and IO, with the DeltaV Virtual IO Module and the Modbus TCP/IP Driver. The testing was completed in MYNAH Technologies testing lab in Chesterfield, MO, USA. The following was tested and documented:
Device Tested: Wago 750-841 Ethernet TCP/IP Programmable Fieldbus Controller.
The unit was shipped to MYNAH from the Wago headquarters in Germantown, WI. The test unit was pre-wired and assembled and included the following components:
The 750-841 controller was configured using the Wago Ethernet Settings Utility v3.00.03. The unit was set up for default Modbus TCP/IP communications with Ethernet/IP communications disabled. A configuration summary is as follows:
Per the user manual, the IO data for the 750-841 is represented in a process image table. Inputs are written to the input table with a starting address of 0, and can be read by the Modbus master as input registers. Outputs are read from the output table with a starting address of 512 and can be written by the Modbus master as holding registers.. Analog values are written to the first registers in the order of their placement in the IO rack, and discretes are written to the same registers following all AI values. Changing the location of the IO modules will change the placement of field values in the process image table.
The DeltaV Virtual IO Module was configured with MYNAH Technologies’ VIMNET Explorer, v18.104.22.168. A configuration summary is as follows:
|Driver||Modbus TCP - Simplex|
In the VIMNet Explorer application, the 750-841 controller was setup as device DEV01, using RTU TCP (port 502) communications and a Modbus address of 1.
DeltaV v7.3 build 4069 was used for the testing. A new controller was commissioned, the Virtual IO Module was sensed as Prgrammable Serial Modules slots 57-60, and PO1 of card 57 was enabled. One device (for the 750-841 controller) and two datasets (input dataset and output dataset) were configured. A summary of the device and dataset communication is as follows:
|DS01 data direction||Input|
|DS01 DeltaV Data Type||16 bit uint w/ status|
|DS01 Device Data Type||2|
|DS01 Data start address||0|
|DS01 Number of values||10|
|DS0 data direction||Output|
|DS02 DeltaV Data Type||16 bit uint w/ status|
|DS02 Devise Data Type||3|
|DS02 Data start address||512|
|DS02 Number of values||10|
A DeltaV Module was built called WAGO_TEST for displaying the input and output registers from the 750-841 controller and for testing purposes. Analog IO values were displayed as unscaled 16 bit registers. Discrete IO values were displayed as individual bits after being extracted from the register using the BFI and BFO function blocks. A CALC block was used to cycle the output signals to the DO in the field upon each scan for tieback testing. The module was run at 100 msec for tieback performance testing.
Tieback testing of DIO performance was run using the module described above. Analog IO was tested for continuity only and not for tieback speed. All output channels were hardwired at the IO card to the corresponding input. As stated before, the test module was given an execution time of 100 msec. The tests were run for 15 sec burst loads with all Discrete outputs cycled every module scan. Approximately 1000 data events were analyzed to determine the statistics below. Changes to the discrete output channels and the discrete input channels after the Boolean fans were logged into the DeltaV event journal. A summary of the testing results and DeltaV performance indicators is as follows:
|DeltaV Module Execution Time||100 msec|
|Avg Discrete Tieback time||100 msec|
|Max Discrete Tieback Time||101 msec|
|Min Discrete Tieback Time||99 msec|
|Serial Port Max Scan Time||10 msec|
|Serial Port Avg Scan Time||4-7 msec|
|MD Controller Free Processor Time||100 MD|
|MD Controller Free Memory||15661088|
Performance Summary and Other Observations:
In summary, we found no problems in using the Wago 750-841 Ethernet TCP/IP Programmable Fieldbus Controller with DeltaV and the Virtual IO Module. Communication speed and performance was as expected and we had no problems with the device in setup or testing.
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Chesterfield, MO 63017 USA
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