Troubleshooting Known Issues

Q: The Value in MinPs 1 becomes -2,000,000,000 or its value is greater than Ps_psig.

Affects : Versions 0.50 to 1.1.13 mCore Symptoms : The MinPs1 (ACI_Control[8], Modbus Reg #40291) and/or the MaxPs1 (ACI_Control[9], Modbus Reg #40293) give a value that can inadvertently be considered as a safety issue that then can result in shutting the unit down. Typically this happens when the current operating point is at full torque (or at unit’s derated torque maximum). Workaround : Add the following logic when setting the MinPs1 and MaxPs1 values: IF ACI_Control[8] > Ps_psig AND Error_Array[CurrLS] = 0 THEN MinPs1 = ACI_Control[8] = 0.99*Ps_psig ELSE MinPs1 = ACI_Control[8] IF ACI_Control[8] = -2e+09 AND Error_Array[CurrLS] = 0 THEN MinPs1 = ACI_Control[8] = 0.99*Ps_psig ELSE MinPs1 = ACI_Control[8] IF ACI_Control[9] = -2e+09 AND Error_Array[CurrLS] = 0 THEN MaxPs1 = ACI_Control[9] = 1.01*Ps_psig ELSE MaxPs1 = ACI_Control[9] This will be fixed in a future firmware version.

Q: Data is being sent to eRCM Express, calculations appear to be completed, and most data seems to be returned. However, some data items are missing or not changing when they should.

Affects : Affects all versions. Symptoms : When reviewing returned data, some items do not change or are not populated by the correct numbers. This generally only happens when eRCM Express is in its Allen Bradley Communications Mode. Cause-1: There is an array size discrepancy between the eRCM Express and the Allen Bradley, on one or more arrays. Hence, some data may be overwriting other data causing incorrect values to be appear. Cause-2: Some code at the Allen Bradley is writing data into the array area to which the eRCM Express is sending data. That area should be strictly Read-Only for the Allen Bradley. Some data items are only sent when changed (via the eRCM Express) and hence if the PLC changes that data, it may never get updated again with the correct data from the eRCM Express. Solution: Make sure that the array sizes in the Allen Bradley are the same sizes as the arrays that the eRCM Express is sending to the Allen Bradley. If still encountering issues, please contact Monico so they can review array sizes as determined by the eRCM Express. Planned Fix: None planned. Changing array sizes is a feature that can be used to minimize the amount of data being transferred which may be desirable at times. However, source and destination arrays must both support the exact same dimensions, or data corruption become possible.

Q: For 2-Stage models only, flow rates and power from eRCM Express per load step do not match well to eRCM Viewer predictions at the same operating conditions for most load steps.

Affects : Version 1.0+ of mCore. Symptoms : eRCM Express returns identical flow rates for most (or all) load steps, and/or the predicted power does not match eRCM Viewer model at most of the load steps. This only applies to 2-Stage models. Workaround : This happens when data is written into the special tags received for a special 2-stage mode of operations (only used by a few end users, and then only rarely used). Thus, to prevent this, do not write any data into the following tags: AB tags ACI_Inputs[30]..ACI_Inputs[36]; or Modbus Registers 40061..40073. Issue (to be) fixed in Version 3 of the eRCM Express/Monico mCore.

Q: Uploading a valid eRCM Express licensing file sometimes does not correctly copy that file into the mCore and results in a zero-byte file being created in the mCore. Internally, the mCore is not licensed to use eRCM’s calculation methods, and thus does not return useful results.

Affects : Version 0.5.0 and 0.5.1 of mCore. Symptoms : Static items Ranges, Number of Load Steps, etc. are still returned, but all registers with performance and control items are returned as zeroes. Note : This issue would only occur if the license file was accidentally removed and the user is trying to re-license the mCore, or if the user is upgrading unit from a Condition Monitor license to an eRCM Express license. Workaround : In the web interface, click the Clear ACI License File button, then reupload the provided license file. If issue is not resolved, try repeating above workaround a couple of times.

Q: Uploading valid eRCM Viewer files sometimes does not correctly copy those files into the mCore and results in some zero-byte files being created in the mCore that cannot then be used.

Affects : Version 0.5.0 and 0.5.1 of mCore. Symptoms : The desired eRCM Viewer file is included in the list of files in the web interface, but when retrieving compressor calculations, all values are zero — all the time. Workaround : In the web interface, click the Clear All Viewer Files button, then navigate to the Import Viewer files upload page and upload the eRCM Viewer files again. If issue is not resolved, try repeating the above workaround a couple of times.

Q: Next load step up/down does not return sensible results when using “Field_Ps” feature.

Affects: Version 0.5.0 to 1.1.31 mCore. Symptoms : When passing a value in the “Field_Ps” tag, next load step up/down results will not be correct for the current load step. Workaround : Write a value of “0” (zero) for the “Field_Ps” input tag value. This will turn off that feature and next load step up/down will be correct.

Communication Settings with the Allen Bradley PLC appear to be configured, but no communications happen.Krystle Rombach2025-07-24T20:30:44+00:00

Communication Settings with the Allen Bradley PLC appear to be configured, but no communications happen.

Check the IP number. It needs to be the IP of the “card” that it talks through, and the Slot Number must be that for the Processor. Generally, you do not use the IP number of the PLC itself.

The Value in MinPs 1 becomes -2,000,000,000 or its value is greater than Ps_psig.Krystle Rombach2025-05-05T18:39:57+00:00

The Value in MinPs 1 becomes -2,000,000,000 or its value is greater than Ps_psig.

Affects: Versions 0.50 to 1.1.13 mCore
Symptoms: The MinPs1 (ACI_Control[8], Modbus Reg #40291) and/or the MaxPs1 (ACI_Control[9], Modbus Reg #40293) give a value that can inadvertently be considered as a safety issue that then can result in shutting the unit down. Typically this happens when the current operating point is at full torque (or at unit’s derated torque maximum).
Workaround: Add the following logic when setting the MinPs1 and MaxPs1 values:
IF ACI_Control[8] > Ps_psig AND Error_Array[CurrLS] = 0 THEN MinPs1 = ACI_Control[8] = 0.99*Ps_psig ELSE MinPs1 = ACI_Control[8]
IF ACI_Control[8] = -2e+09 AND Error_Array[CurrLS] = 0 THEN MinPs1 = ACI_Control[8] = 0.99*Ps_psig ELSE MinPs1 = ACI_Control[8]
IF ACI_Control[9] = -2e+09 AND Error_Array[CurrLS] = 0 THEN MaxPs1 = ACI_Control[9] = 1.01*Ps_psig ELSE MaxPs1 = ACI_Control[9]

This will be fixed in a future firmware version.

Data is being sent to eRCM Express, calculations appear to be completed, and most data seems to be returned. However, some data items are missing or not changing when they should.Derrick Oliver2024-12-12T18:43:06+00:00

Data is being sent to eRCM Express, calculations appear to be completed, and most data seems to be returned. However, some data items are missing or not changing when they should.

Affects: Affects all versions.
Symptoms: When reviewing returned data, some items do not change or are not populated by the correct numbers. This generally only happens when eRCM Express is in its Allen Bradley Communications Mode.
Cause-1: There is an array size discrepancy between the eRCM Express and the Allen Bradley, on one or more arrays. Hence, some data may be overwriting other data causing incorrect values to be appear.
Cause-2: Some code at the Allen Bradley is writing data into the array area to which the eRCM Express is sending data. That area should be strictly Read-Only for the Allen Bradley. Some data items are only sent when changed (via the eRCM Express) and hence if the PLC changes that data, it may never get updated again with the correct data from the eRCM Express.
Solution: Make sure that the array sizes in the Allen Bradley are the same sizes as the arrays that the eRCM Express is sending to the Allen Bradley. If still encountering issues, please contact Monico so they can review array sizes as determined by the eRCM Express.
Planned Fix: None planned. Changing array sizes is a feature that can be used to minimize the amount of data being transferred which may be desirable at times. However, source and destination arrays must both support the exact same dimensions, or data corruption become possible.

For 2-Stage models only, flow rates and power from eRCM Express per load step do not match well to eRCM Viewer predictions at the same operating conditions for most load steps.ACI Services2024-03-14T15:19:30+00:00

For 2-Stage models only, flow rates and power from eRCM Express per load step do not match well to eRCM Viewer predictions at the same operating conditions for most load steps.

Affects: Version 1.0+ of mCore.
Symptoms: eRCM Express returns identical flow rates for most (or all) load steps, and/or the predicted power does not match eRCM Viewer model at most of the load steps. This only applies to 2-Stage models.
Workaround: This happens when data is written into the special tags received for a special 2-stage mode of operations (only used by a few end users, and then only rarely used). Thus, to prevent this, do not write any data into the following tags: AB tags ACI_Inputs[30]..ACI_Inputs[36]; or Modbus Registers 40061..40073.
Issue (to be) fixed in Version 3 of the eRCM Express/Monico mCore.

Uploading a valid eRCM Express licensing file sometimes does not correctly copy that file into the mCore and results in a zero-byte file being created in the mCore. Internally, the mCore is not licensed to use eRCM’s calculation methods, and thus does not return useful results.elliott2023-05-09T21:10:32+00:00

Uploading a valid eRCM Express licensing file sometimes does not correctly copy that file into the mCore and results in a zero-byte file being created in the mCore. Internally, the mCore is not licensed to use eRCM’s calculation methods, and thus does not return useful results.

Affects: Version 0.5.0 and 0.5.1 of mCore.
Symptoms: Static items Ranges, Number of Load Steps, etc. are still returned, but all registers with performance and control items are returned as zeroes.
- Note: This issue would only occur if the license file was accidentally removed and the user is trying to re-license the mCore, or if the user is upgrading unit from a Condition Monitor license to an eRCM Express license.
Workaround: In the web interface, click the Clear ACI License File button, then reupload the provided license file.
- If issue is not resolved, try repeating above workaround a couple of times.

Uploading valid eRCM Viewer files sometimes does not correctly copy those files into the mCore and results in some zero-byte files being created in the mCore that cannot then be used.elliott2023-05-09T21:10:20+00:00

Uploading valid eRCM Viewer files sometimes does not correctly copy those files into the mCore and results in some zero-byte files being created in the mCore that cannot then be used.

Affects: Version 0.5.0 and 0.5.1 of mCore.
Symptoms: The desired eRCM Viewer file is included in the list of files in the web interface, but when retrieving compressor calculations, all values are zero — all the time.
Workaround: In the web interface, click the Clear All Viewer Files button, then navigate to the Import Viewer files upload page and upload the eRCM Viewer files again.
If issue is not resolved, try repeating the above workaround a couple of times.

Next load step up/down does not return sensible results when using “Field_Ps” feature.elliott2023-05-09T21:10:08+00:00

Next load step up/down does not return sensible results when using “Field_Ps” feature.

Affects: Version 0.5.0 to 1.1.31 mCore.
Symptoms: When passing a value in the “Field_Ps” tag, next load step up/down results will not be correct for the current load step.
Workaround: Write a value of “0” (zero) for the “Field_Ps” input tag value. This will turn off that feature and next load step up/down will be correct.

Communications between the PLC and the eRCM Express box seem to be working, but only zeroes are being returned for most all tags/registers.elliott2023-05-09T21:09:57+00:00

Communications between the PLC and the eRCM Express box seem to be working, but only zeroes are being returned for most all tags/registers.

Check that the eRCM Express License is installed and valid on the mCore.
- How to do: See the section “Uploading a License File” in the eRCM Express Manual.
Check that at least one (1) eRCM Viewer model has been uploaded to the mCore and that the model names start with a digit (“1” through “9”)
- How to do: See the section “Uploading a License File” in the eRCM Express Manual.
Check if the PLC is sending any data in ACI_Input[50] (SetViewerFile, Modbus Reg# 40101). This item is used to specify which eRCM Viewer model to be used within the eRCM Express.
- Values less than zero (0) or greater than nine (9) are ignored.
- A value of zero (0) tells eRCM Express to take no action, and to keep using the current modeling file.
- A value from one (1) to nine (9) tells the eRCM Express to load in the eRCM Viewer models starting with that digit.
- In generally, this item’s value should be zero (0) if only one file is in the eRCM Express box, and this item never needs changed.
- If multiple models are in the eRCM Express box, then this item’s value should only get set during Unit Start Up, and thereafter reset to zero (0).
- If a value in ACI_Inputs[50]/Reg#40101 sets eRCM Express to a non-existent unit (i.e. no modeling file starting with that specified digit), then no data will be returned, and all data items will stay at their initial values of zeroes (0).
If you are using the Allen Bradley communications option, please check to make sure that the setup in the mCore is correct for your Allen Bradley PLC. Specifically, the mCore needs to be set with the IP of the Allen Bradley PLC. If the mCore cannot push data to the PLC, then likely the results will be that the data you send to the mCore will be there in the mCore but data in the PLC will likely remain all zeroes (0’s).
- Click here to view a PDF for instructions on how to set/confirm the Device IP.
If some data appears updating while other data appears to not update, then the issue may be with the size of the arrays allotted to the data being sent from the mCore. If the local AB arrays are the correct size (or even larger than the mCore arrays), there should be no issues. However, if the local AB arrays are smaller (i.e., fewer elements), then communication issues will persist and data will be corrupt, missing, or may not even update.

Next Step Up and Next Step Down, and all Load Step are invalid when trying to “pack” a discharge lineelliott2023-05-09T21:09:36+00:00

Next Step Up and Next Step Down, and all Load Step are invalid when trying to “pack” a discharge line

* e.g., very low compression ratios.

Likely the issue is the model (eRCM Viewer file) is using a MinRatio limit higher than 1. Hence, if compression ratio goes lower than set MinRatio, then all load steps are affected and thus all load steps area flagged as unusable.

Affects: All Versions.
Symptoms: All load steps flagged as unsafe.
Workaround: 1) Create a new eRCM Viewer file with a MinRatio of 1.00 and upload that new file into the eRCM Express.
- Note: This is a useful constraint feature, and not a bug. However, most models default to a MinRatio of 1.02 which can lead to operating issues when packing a discharge line.

When changing from one eRCM Viewer model to another, via the mCore UI or from the PLC via tag/register changes, the mCore does not synch the PLC’s specified Load Step with the internal model’s current Load Step, leaving the eRCM Express still set to Load Step #1 (the default load step number when a new model is loaded).elliott2023-05-09T21:04:12+00:00

When changing from one eRCM Viewer model to another, via the mCore UI or from the PLC via tag/register changes, the mCore does not synch the PLC’s specified Load Step with the internal model’s current Load Step, leaving the eRCM Express still set to Load Step #1 (the default load step number when a new model is loaded).

* This issue only applies when changing eRCM Viewer models (via the PLC or via the mCore UI).

Affects: Some versions of Version 2.
Symptoms: The eRCM Express data after the file change does not reflect the correct data for the specified Current Load Step, and returned results often have Next Step Up, Next Step Down, and Ideal Load Step all set to -1’s.
Workaround: Via the PLC, after loading in a new eRCM Viewer model (usually done while the unit is in idle/bypass mode), the Current Load Step is usually the least-loaded load step. Thus, if this is LS#15, then set to LS#14, update the eRCM Express, then return to LS#15, and update the eRCM Express. Continue as normal with starting the unit. All data will now be synched correctly.
Planned Fix: A new version of the firmware will correct this issue. Thereafter the workaround is no longer needed.