Modbus Resource Sheet

Modbus Comms Information

Proface Modbus Explained Serial vs. TCP

https://www.youtube.com/watch?v=k993tAFRLSE

Articles on Modbus

http://www.automation.com/library/articles-white-papers/fieldbus-serial-bus-io-networks/introduction-to-modbus

http://www.ccontrols.com/pdf/Extv9n5.pdf

RS485/Modbus Wiring

http://www.chipkin.com/rs485-cables-why-you-need-3-wires-for-2-two-wire-rs485/

Honeywell  Standard wire terminals:  A 485+, B 485-, Ground, Shield

http://www.rs485.com/rs485spec.html

Modbus on XNX transmitter

http://www.honeywellanalytics.com/~/media/honeywell-analytics/products/xnx-universal-transmitter/documents/english/1998m0738-xnx-tech-manual-eng-rev12.pdf pg 185-189

https://www.honeywellaccess.com/documents/800-16176_EGR_Tech_Bulletin-Recommended_485_Wiring_for_NX_Loops.pdf

Scott Meridian Gas Detector – includes 4-20 mA and Modbus RTU

https://www.scottsafety.com/en/us/Pages/ProductDetail.aspx?productdetail=Meridian+Universal+Gas+Detector

HART

http://literature.rockwellautomation.com/idc/groups/literature/documents/pp/1756-pp016_-en-p.pdf

http://en.hartcomm.org/hcp/tech/aboutprotocol/aboutprotocol_how.html

 

SCADA Demo with Modbus TCP and RTU over TCP

https://www.inductiveautomation.com/

Wireless Modbus  US$121.75

http://gridconnect.com/wireless-modbus.html

https://oceancontrols.com.au/NOW-001.html $400

Modbus TCP versus Modbus RTU over TCP

http://www.simplymodbus.ca/TCP.htm

Modbus servers

http://www.comtrol.com/elements/uploads/fckeditor/file/DeviceMasterUP_ModbusSolutionsExamples_LT1419C.pdf

http://www.anybus.com/products/abs.shtml

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Email Changes

These accounts are active/remain active:
rmah@computer.org (primarily for work)
robert.mah3@gmail.com (primarily for line dance)
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Looking for Projects in Ottawa

Due to changes in personal circumstance I am actively looking for projects in Ottawa.  Past projects I have executed in Ottawa are e-beam evaporators for NRC and environment test chamber for rats with Health Canada research.

My business is manufacturing automation. I execute many one-time projects for the various clients. Most clients return to have further work done.

Reasons why they contract me:

Relieve workload on existing personnel

Fill the gap between engineering and IT. Real-time data collection of production or process information into a database like Oracle is a lot different from business applications.

Provide Engineering mentoring for younger employees

Workstation re-fits. Existing controls or display screens are obsolete and need replacement but PLC control needs to be reverse engineered and re-programmed for the new system.

Control system issues that cannot be resolved. I have experience in electrical, electronic and control systems.  This lets me find problems and solutions that may not be apparent to individual specialists.

I provide outstanding service at a fair price.

I execute projects within client timeline requirements.

Typical Project:

http://rmsystems.ca/older-projects/ecr-deposition-using-rf-plasma/ (Many others shown here)

Please contact me if you or anyone you know have requirements like these.

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New Website

In process of moving all pages over to WordPress.  Sympatico home page will be retired soon after 15 years of Frontpage.

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Outlook Express Inbox Problems

I’ve had a problem with Outlook Express for 2 days.  I couldn’t get any new mail to appear.  It would get the message count from the server and then error out.  I looked on the Bell site for potential solutions, server alerts or config. changes.  I guess I spent a lot of time so a tech chat session popped up.  I said OK and the tech played around and re-checked everything I did.  In fact by the time he left, I had another error popping up on all my old messages.  He said he didn’t know and to clear out my inbox.  Well I tried clearing it but I noticed some messages wouldn’t move but ended up duplicating.  So I ran the folder compacting utility and that fixed it.

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Fieldbus Obsolete

I have 5 laptops for a reason.  They are loaded with old software for client projects.  An example is a client had a Omron analog input module go bad on them (no power lights).  It was a remote DeviceNet module I had installed for them in 1999.  Replacement part was 4-6 week delivery.  We decided to replace them with Advantech ADAM Ethernet I/O.  Not really a plug-in replacement but a newer design.  All DeviceNet I/O I could find seemed obsolete, limited or no stock and relatively expensive.

In order to do that, I needed to re-program the Omron DeviceNet master and remove 4 of the 9 nodes that were defined.  Easily said but the programming card I have is a ISA card.  I kept a Compaq laptop with a docking station with a ISA slot for this purpose.  I’ve used it a few times over the last few years.  This time the computer would not boot.  Just a flashing orange light.  No BIOS page.  Reseated the memory SIMMS but I think it’s really dead, as I should have at least a memory test fault.

So I look for an old desktop that had a ISA slot.  First one I booted had Windows 95.  That seemed too scary to proceed.  The second one had Windows 98.  I loaded the software.  No card detected.  I had to pullout the old manual. Luckily I wrote inside IO addr 280, memory D000.  Oh so ancient.  But the software came up.  I read out the old config and went to load the modified config.  Error “Module in an invalid state”.  Then I remembered I need to put the PLC in the program state.  No keyswitch so I need the software.  It is only loaded on my very first laptop I owned, Hitachi with Windows 95.  Yeah still boots.  Went in the software changed to program mode and finally downloaded the new module config.  I really feel I’m teettering on the brink of obsolence.

DeviceNet really lost out in the Fieldbus wars.  Not many left.  The trouble is most manufacturing equipment runs until it really wears out.  That can easily be in excess of 15 years.

Updating I/O technology I feel is going to Ethernet.  Ethernet/IP and Modbus-TCP are the ones I deal with the most.  I’ll need to evolve client’s systems as I can.

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Dry Storage of Nuclear Waste

Two stage drying control removed water without freezing then pulls the dry storage container to full vacuum, ready for next operation of Helium fill and leak checking.

Implementation

Single cycle control runs roughing, drying and final vacuum.  Various critical alarms are annunciated including end of cycle.

Benefits

Live Trending allows for unattended operation.

Vacuum setpoints and timer settings on screen allow for process refinement.

Settings are password protected.

Technical Details

Allen Bradley MicroLogix 1100 processor with serial port and Ethernet.

Visual Basic 6 application.  Touchscreen built into panel.

Trend data stored in MS Access as well as live trends using Gigasoft charts.

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ISRO India Space Agency Cryo Cooler Nov 2004

ISRO India Space Agency Cryo Cooler

ISRO Cryo Cooler Graphic Display

Load Cell Controls Stepper Motor to provide zero pressure on connecting flange.

Cryo Stepper Strain Relief

Implementation

Redundant Cryo Bench Cooler for India Space agency. Used to test satellite components in a vacuum chamber. Some tests can run for months and requires 100% uptime all components were built as dual redundant, including PLC I/O and power supplies.

Dual Turbo Pumps evacuate the chamber attached to the flange. During pump out and cool down no strain can be placed on the flange a load cell connects to an Oriental Motor Stepper and maintains zero strain.

Systems is Programmed in Visual Basic with MS Access process and datalogging. Databases are periodically replicated to back-up storage and data servers.

Benefits

  • Automated pump down and vent
  • Automated process data collection
  • Data files are accessible from any workstation via wireless Ethernet and also wired connections.

Technical Details

Controller:  AB SLC 5/05 Controller communications:  Ethernet to HP Computers.
Operating System:  WIN XP Pro
Software:  Visual Basic 6
Network:  100BaseT, Wireless 802.11b
Trending Software:  IOComp
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