Emergency VFD Replacements at a Level 1 Trauma Center

Last weeks multiple massive thunderstorms caused major power dips, voltage spikes/surges, voltage fluctuations, phase losses and generator switch-overs. All of these electrical events  can create havoc upon sensitive electronic devices. VFDs are no exception.

During these storms with all of the electrical activity occurring, 4 separate, critical VFDs running air handling systems throughout the hospital unit failed. Clean, filtered air flow is a necessity in these locations. Delta was called to evaluate these failed units on an emergency basis. The hope was that Delta could quickly repair these VFDs. Unfortunately, all 4 of the units were damaged beyond any economical repair. Delta immediately provided 4 new replacement VFDs and had them all retrofitted into the old VFD panels, up and running, overnight.


Delta Automation is Prepared to Assist any or all of our clients in the the wake of the Hurricanes

Graphic courtesy of NOAA

cone graphic

Delta Automation is prepared to assist any or all of our clients that were in the path of Harvey or may be in the path of  Irma. Our stock of new and refurbished equipment is ready to go to get you or your clients equipment up and running as soon as possible.

Our field service team will be on alert to assist with any on-site needs as well.         Please don’t hesitate to contact us via phone or email!

804 236 2800 or 1 888  PC DELTA          Email:  sales@deltaautomation.com


Consequences of Duplicate Addresses on a ModBus Plus Network

As with any addressable network, having duplicate addresses is an issue. On Modbus Plus networks, one of three things can occur. Modicon technical support disagrees on this subject but in my 30+ years of working with these networks all over the world, I have proven differently many, many times.

The first, and most likely event to occur,  the node that is being added to a network with the same address, will simply not be allowed to join the network.

The second thing that may occur, the node that is being added to the network will displace the existing node with the same address, assuming its’ place upon the network.

The third thing that may occur, is that when connecting the new node to the network with an existing node address is that the two nodes alternate joining and dropping off of the network.

The second and third options are obviously not desirable results. For this reason ALWAYS be certain of what addresses are existing on any given network. Utilizing a network discovery tool such as MBPStat, should eliminate any dual addressing.

Very recently, while performing a quick troubleshooting procedure upon a Modbus Plus network, I found a unique situation. I knew that I had a duplicate address on my computers’ PCMCIA card. however the plant was down, with no equipment running , and I was just doing a quick error check after repairing an illegal splice on the network. I was located at the MB+ repeater between segments 3 and 4 of this network. I monitored segment 3 for errors, all was OK, then I monitored segment 4 for errors, again all was OK. I reconnected the cables back to the repeater and then went to the end of segment 4 to monitor the entire network for errors. I was surprised to see all “U”‘s on every node! Those familiar with MBPStat, know that this indicates the monitor cannot properly identify the nodes. I went back to the repeater and checked both segments individually, again, all was OK. It was then that I remembered that I was utilizing an already assigned node address. I suspected this may be the issue. I again reconnected the cables back to the repeater, went to the end of segment 4,  reset the address to a non-assigned node address. Upon checking the network monitor, it now showed all nodes properly with no errors.This further illustrates the unusual results which may occur in the event of a dual node address.

This is even more reason to be aware of existing addresses when adding any nodes to a network!

Delta Automation Supports Our American Veterans

Joe @ McGuire's VA Gig (Medium)One of our employees, operations manager, Joe Sarver, put his alter-talent to good use as he lent a musical helping hand to entertain a room full of most appreciative men and women military veterans from all branches of the service including the US Coast Guard.

Joe performed a one hour, weekday afternoon Valentine’s benefit concert with the Tommy Witten Quartet at the Sitter-Barfoot Veterans Care Center of McGuire Veterans Medical Center located in Richmond, VA. Much to the delight of the vets, the band played requests and concluded the concert with a medley of theme songs for each branch of the service represented there. A fun time was had by the veterans, the medical staff, and the band!


Pictured above is Joe posing with his venerable 165 year old bass, below the Veterans facility.

McGuire's VA Hospital Center (Medium)

Cloud Chamber Fully Operational And The Grand Opening To Unveil It Goes On As Planned Thanks To Delta Automation

Delta Automation was contacted recently by the manufacturer of a cloud chamber (a physics experiment apparatus used to study sub-atomic particles and radiation naturally occurring in air) built in Germany.   See the cloud chamber in operation at this link: http://www.youtube.com/watch?v=kKur0QcLkd4


The cloud chamber, recently installed at a high school’s new Science and Technology Wing located in northern Virginia, was not operational. This is because its Danfoss dual compressor cooling unit would not stay on line due to issues with a power converter that allows the system to operate on US power. The cloud chamber manufacturer searched Danfoss tech support and found Delta Automation as an authorized service provider.

With the deadline for the grand opening ceremony rapidly approaching, both the manufacturer and the school’s personnel were panicking to get the cloud chamber fully operational. Once Delta was contacted by the cloud chamber manufacturer, Delta’s field service engineer Skip Langley, was dispatched immediately to investigate the issue. Skip quickly determined that the power converter was not large enough ampacity-wise to handle the dual compressor load. Upon obtaining and installing a new and more robust power converter that Delta arranged to obtain here in the US, along with making some changes to the way the apparatus was fed by building power, Skip was able to restore the cloud chamber to full operation just in time for the grand opening.

While this is the first and perhaps only cloud chamber Delta Automation will ever perform service on, we were happy to take on the challenge. Because of our commitment to always try and help a customer, we were able to play a major part in helping to save the day for a successful Grand Opening.

Heat Tracing short located with a TDR

heat trace1 heat trace2 heat trace3One of Delta’s long time clients called with an unusual request inquiring if a TDR could be used to help locate a short circuit in a section of heat trace wiring.  This client has had Delta TDR its’ PLC communication systems for years and knew of our expertise in utilizing the equipment.

We responded to the request with a “I don’t know, but we are willing to try it!” If successful, this could prevent the replacement of hundreds of feet of heat trace wiring, plus all of the removal and re-installation of the insulation and protective metal cladding. Arriving on-site within the hour, we were met by the electrical contractor at the clients’ site. He had contacted the heat trace wiring manufacturer, and was informed that this cable could not be checked that way and told us of that conversation. We still decided to proceed with the testing/troubleshooting. A 10 foot sample of the heat trace wiring was obtained to calibrate the TDR to the proper VP of the cable. During this calibration process, we shorted the cable to determine if the TDR could detect the short. We easily determined that this was the case and continued with the calibration. Once that was completed, we connected the TDR to the suspect cable. and determined that there was a short at approximately 19 feet from the test location between one conductor and the shielding. The electrical contractor, using a tape measure, measured the distance from the TDR to a point on the piping, 19 “cable feet” away. The metal cladding and insulation had to be removed in that vicinity. As the contractors were removing the metal cladding we noticed that the “short” indication on the TDR was intermittent. This information proved that we were near the short, and was relayed to the contractor. As they continued to remove the metal cladding, in the process of removing a sheet metal screw, the short disappeared! Success!

After the remaining metal cladding and insulation were removed, it was evident that the sheet metal screw had penetrated the heat trace cable causing the short.

This exercise prevented the cost and time involved in replacing all of the several hundred feet of cable, insulation and metal cladding.

Delta proved that its’ willingness to assist the client in any way possible is at the center of our core business.

Heat trace wire: Electrically resistive cable utilized to prevent piping from freezing during low temperatures.

TDR: Time Domain Reflectometer, specialized test equipment utilized for testing communication cables such as coaxial and twisted pair cables.

VP: Velocity of Propagation, the “speed” of electrical signals within a cable reference as a percentage of the speed of light ( I.E. 82%).