As the Rockwell Encompass Partner for dynamic simulation, MYNAH Technologies offers users the option to manually convert simulation projects from Rockwell Automation’s RSTestStand™ to Mimic Simulation Software or to utilize our expertise through cost effective model migration services.
For users who wish to do this conversion themselves, MYNAH has collaborated with Rockwell Automation to develop a procedure to be used in transitioning from RSTestStand™ to Mimic. This manual solution outlined here has been tested and is fully supported.
In this procedure, it is assumed that the user has access to RSTestStand™ software, can use the “Logic View” on each resource template as needed, and can view the variables/tags used to configure these resources. The table below outlines the major sections of the procedure for converting each piece of the RSTestStand™ project into its equivalent part of Mimic.
|RSTestStand™||Mimic Simulation Software|
|Tags/Variables||SIOTags (Ethernet/IP IO Definition)
SIOTags (OPC IO Definition)
|Operator Console||Graphic View|
There are a few important differences between the two simulation programs that may prevent a migrated project from being completely identical to the original. First, time does not run the same way in models as it does in the logic flowcharts in resources; “scans” are used as time in Mimic. Where some logic flowcharts will show a block featuring “Pulse (0.25),” for example, Mimic would perform this task once each scan instead of each 0.25 seconds. Mimic defaults to one second between scans.
Along these lines, the Delay Time resource cannot be modeled in Mimic because the duration of a time cannot be declared at runtime. This resource would be equivalent to a Dead Time Block if the block’s duration was dynamic. It could be possible to do this with a loop structure in a Calculation (Calc) Block using the TIME variable, but the Calc Block’s loop until functionality is limited to 100 iterations.
Additionally, the Excel Data Array resource does not have a Mimic equivalent. This functionality cannot be captured as is because Mimic does not support the ability to read data from an external source in the way that this resource references columns from an excel spreadsheet to populate an array.
Aside from the exceptions above, all remaining standard resources (those with templates available in the RSTestStand™ Software) can be converted into an equivalent or nearly equivalent Mimic model. Standard resources and their matching blocks are shown in the table below. For more detailed information about each block in Mimic, the Help Files can be accessed by right-clicking on the block and selecting “What is this?”.
|RSTestStand™ Resource||Mimic Block(s) to Make Model|
|Simple Axis||Simple Axis|
|Rotary Axis||Rotary Axis|
|Velocity_Position Axis||Velocity Position|
|Sine Wave Generator||Signal Generator|
|Duty Cycle Timer||Pulse Generator|
|Random Amplitude Generator||Randomizer|
|Shift Register||Shift Register|
|Generic VFD||Generic VFD|
|Fixed Speed ON Pump||Simple Pump with RPM Calc Block|
|Variable Speed Pump||Simple Pump with Variable RPM Calc Block|
|Timer Delay||Dead Time|
|Flip Flop||RS Flip-Flop|
|Message Array Example||Message Array|
|Momentary Latched MOV||Momentary Latched MOV|
|On_Off Valve||On Off Valve|
|Motor Operated Valve||Motor Operated Valve|
|Analog Valve||Analog Valve|
|Integrator||Integrator and check limits with Conditional|
|Limiter||Minimum with IParam set to limit|
|Second Order Lag||Second Order Filter|
|First Order Lag||First Order Filter|
For users that need to convert custom RSTestStand™ resources to Mimic models, Calc Blocks should be used. These blocks allow the user to specify the script carried out by the block. Following the suggestions below should help the user to generate a Mimic model based on the flowchart provided in the “logic view” of the resource.
There are also a few blocks in Mimic, but not RSTestStand™, that are needed in conjunction with the mentioned modeling blocks in order to fully simulate a resource in Mimic. An Input Parameter (Iparam) Block will be needed for each variable that is an input to the resource (found by going to the “Variables” tab of the “Properties” window for the resource). Output variables that need to be referenced will also need similar accommodations (using an Output Parameter, or Oparam, Block).
Variables associated with tags will also need to use separate blocks to communicate with Mimic’s Simulated IO Tags (SIOTags). This is done with Analog Input or Analog Output Blocks. Writing from the model to the controller requires an Analog Input (AI) block, while reading from the controller requires an Analog Output (AO) block. Block references will need to be specified via arrows connecting blocks or by using path references to connect blocks in the same or different models.
When multiple bits of a word contained in a SIOTag need to be written to or read from, the Boolean Fan In/Boolean Fan Out (BFI/BFO) Block will need to be used. Note that the controller indexes for the bits start at zero, so the index in Mimic will be one greater. For example if the tags in RSTestStand™ are Local:1:I.Data/6 and Local:1:I.Data/7 and the values are being read from the controller, the model would require that the AO Block feeds into a BFO Block so that outs 7 and 8 can be selected exclusively and connected to Output Parameter Blocks.
Conversely, if the RSTestStand™ was writing to Local:1:I.Data/4 and Local:1:I.Data/5, the values will be written into a BFI block as shown.
In this case, we cannot simply write into the 5th and 6th bits of Local:1, because the state of all of the other bits need to be saved. To fix this, BFO and AO Blocks reading from the same tag are used to keep all of the other bits constant.
Two different options for users to create IO Definitions are outlined here. Users may choose to create Ethernet/IP or OPC IO Definitions based on the connection they wish to simulate. After the instructions for generating each of these IO Definitions, the steps to connecting the SIOTags to the blocks in the models are listed.
EtherNet/IP IO Definition:
OPC IO Definition:
Now that all of the SIOTags are created, all of the AO and AI Blocks in the models can be connected.
Creating a Graphic View in Mimic is done by right clicking “Views” in Mimic’s Simulation Database and selecting “New” and “Graphic View.” With this view, components can be added to create a visual based on a P&ID, organize training scenarios, simulate a control panel, and more. Nearly all Op Console Devices have an equivalent Mimic Component. The table below shows the Components that correspond to Devices in RSTestStand™. Each component can be configured and customized by right clicking on it and selecting “Properties.”
|RSTestStand™ Op Console Device||Mimic Component(s)|
|2 State Feedback||Switch, AI Block, Dead Time Block, AI Block, and LED|
|Meter||Vertical/Horizontal Bar Graph|
|Push Button||Push Button|
|Selector Switch||Knob + Conditional Block|
|Strip Chart||Right-Click “Views,” and select “New” and then “Trend View”|
|Text Box||Comment Block|
|Thumb Wheel||Vertical Slider with limits [0, (10^Digits)-1]|
If the error message “Could not browse the service list: Could not create the OPCEnum Instance. Access is Denied” appears while creating the Open OPC IO Definition, then OPC items are not being enumerated from the target machine or credentials need to be corrected.
While generating IO Defintions, if the server required is not listed, ensure it is running on the server machine entered into the SERVER_MACHINE field.
MYNAH has many other articles available online prepared to help all users of Mimic. For those new to Mimic, our Quickstart Guide and Help Files are very informative starting points. Our support team is also available to answer questions and troubleshoot issues. Contact us using the information below or login and open a support ticket on our website.
For users that would prefer to use our consulting services for this migration, quotes can be requested by contacting MYNAH at firstname.lastname@example.org or by calling +1.636.728.2000 for more information.
MYNAH Technologies LLC
390 South Woods Mill Road, Suite 100
Chesterfield, MO 63017 USA
MYNAH Technologies LLC
390 South Woods Mill Road, Suite 100
Chesterfield, MO 63017 USA
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