12 Channel NEMA 4 Temperature Recorder

The Maintenance Mgr. of a steel plant in the Midwest called with an application for a portable recorder that can measure, record, save and print temperatures of 12 zones in a high temperature oven. We knew we could do it because we recently put together a similar portable recorder for an asphalt plant here in Pennsylvania. That customer wanted a recorder with both type K and type J thermocouple inputs with a strip jack panel for quick disconnect in the field. They use it to provide asphalt production temperature documentation to the state of Pennsylvania when doing a state funded project.


Manufactured for a Steel Plant

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Manufactured for An Asphalt Plant

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One of the challenges was to find a suitable enclosure to house the recorder. Recorders are typically long and narrow. A recorder 6″ x 6″ x 10″ long would require a very large enclosure due to the 10″ depth. Deeper panels generally have a large front panel. Fortunately, we have access to a custom panel manufacturer that supplies us with handmade fiberglass and metal enclosures fabricated to fit the instrument perfectly – and no larger. We even specify front and back hinged doors which facilitates access to the chart and pen up front as well as downloading data to a memory stick. The customer can also easily access wiring through the back door. And of course a nice ergonomic handle for toting it around.

It turned out beautifully. Another satisfied customer. Have a look for yourself –

Tech Tips

How to Check a Thermocouple (Part 2)

Part 2 of a 2 part series with Wayne Cooke Sr.

C. Check for proper polarity. Many thermocouples are terminated with connectors or a transition where it is possible to have a reverse connection. That is, the negative wire is connected to the positive pin of the connector and positive wire is connected to the negative pin. When heat is applied to the thermocouple with the sensor plugged into a temperature tester, the reading will go down as the temperature goes up.

blogNote: It is not unusual to also see what is known as a “double reverse” connection. Here is an example. Customer has a type K thermocouple terminated with a screw cover head on top of a hot furnace. The electrician connects the wire in the head in reverse. Negative to positive and vice versa. He walks back to the controller 50 ft away and observes that the temperature is reading in the negative direction. Obviously he has a reverse connection. Instead of getting the ladder back out and climbing up on top of the hot furnace, he reverses the connection at the terminals of the controller and sure enough the controller reads in the positive direction. Problem solved? No. He must go back and correct the wiring because he still has the chromel wire connected to the alumel and vice versa in the run of wire from on top of the furnace (where the ambient temp in the screw cover head might be 150 F) and the terminals on back of the controller (where the ambient temp might be 70 F). The result is the same as it would be if he used uncompensated copper wire between the 2 connections and the reading will be off by 80 F (150-70 = 80). Remember red is always negative when working with a thermocouple and usually positive in a standard electrical connection so it is easy to get that mixed up.

D. If you want to determine if your thermocouple or the instrument it is connected to is bad, try the following. Disconnect the thermocouple from the temperature controller or PLC input module and short across the 2 input terminals at the controller. If the controller reads ambient at the terminals, the thermocouple is most likely the problem. This is not always true for all controllers as I’ve seen a few where you must connect a thermocouple to the instrument terminals so it is best to take a short piece of thermocouple wire, strip both ends and twist securely at one end to form a junction and connect the other end to the input terminals and see if you read ambient temperature.

Tech Tips

How to Check a Thermocouple (Part 1)

Part 1 of a 2 part series with Wayne Cooke Sr.

A. Check for continuity by using a multimeter set up to measure ohms. Connect the multimeter test leads to the 2 thermocouple leads (polarity doesn’t matter for this test) and if the meter reads 0 or open circuit, then at least one of the thermocouple leads are broken. Could be at the tip and not visible to you or could be somewhere along the lead wire portion of the assembly.

blogIf you do get a reading it should be several ohms (for a short assembly) to 20, 30, 50 ohms or more depending on the lead length. Ex: a 4 ft. length of 20 gauge type J (iron-constantan) lead wire = 1.396 ohms (.349 / ohm per combined ft. x 4)

B. To determine if a thermocouple is grounded or ungrounded, perform this check. Using the multimeter in the resistance measuring mode, connect one lead of the meter to one lead of the thermocouple and touch the other meter lead to the sheath of the thermocouple. The meter should read 0 or open if that lead (or side) of the thermocouple is ungrounded. Repeat test on other lead of thermocouple and observe reading. If open that lead is also isolated from the sheath and the sensor is ungrounded. Grounded thermocouples are more responsive to a change in temperature while ungrounded thermocouples are useful when there is electrical noise in the area of the thermocouple and that noise could be induced into the sensor.

Note: When checking an “ungrounded” thermocouple, it is possible to have some leakage to ground in a mineral insulated thermocouple. It is difficult to keep the magnesium oxide insulation in a mineral insulated thermocouples (MgOs) completely dry. Most of the time this is not a problem when it’s connected to an instrument or PLC input module, even though you might see some resistance to ground in the megaohm or even kilohm range. When the thermocouple is heated in the process, it tends to drive the moisture out of the tube and create better isolation.


W. H. Cooke Tackles Global Climate Change

W. H. Cooke was contacted by the Oak Ridge National Laboratory in Tennessee to quote and supply special high accuracy multipoint temperature sensors for the “SPRUCE” project in Bovey, Minnesota. The sensor assemblies were quite special, took approximately 4 months to procure materials and build. They were all tested prior to being loaded into a van and driven 1250 miles to the job site by Wayne Cooke Sr. and his brother Gary Cooke. Once they located the site (deep inside the Marcell Experimental Forest) the sensors were unloaded and all 50 checked for proper output and to make sure connections were secure after the long overland trek. They were then stored in a mobile trailer for installation at a later date. Read the original story of the SPRUCE project at Northland News Center, republished below.


Bovey, MN (NNC- — Questions about global warming may find answers at a research site north of Grand Rapids. That’s where scientists have begun an unprecedented study into how warming temperatures affect ecosystems.

“This is the grandest, most ambitious, climate-related experiment ever attempted on the planet,” said USDA Forest Service research scientist, Randy Kolka.

Since 2009, Kolka, Paul Hanson with the Oak Ridge National Laboratory, and other researchers have been working on the SPRUCE.

An acronym for Spruce and Peatland Responses Under Climate and Environmental Change Experiment, SPRUCE will measure how peat land ecosystems respond to changing temperatures. Ten, 35–foot chambers in northern Minnesota’s Marcell Experimental Forest will be warmed to different temperatures, ranging from zero to 16 degrees Fahrenheit. Some chambers will have elevated levels of carbon dioxide.

Scientists started warming SPRUCE on August 13. They celebrated the project Wednesday by inviting community members to tour it.

“Our temperature gradient that we’re using is going to really inform these global circulation model, the models that predict our future climate,” said Kolka.

Just as important is the experiment’s location, in the peat lands of north ern Minnesota. Peat lands make up just three percent of the earth’s land surface, but they contain about 30 percent of the carbon found in soil. It’s all that carbon that makes the ecosystems so critical in studying global climate change.

spruce Prototype1

“The two important greenhouse gases that are leading to the warming of our planet are carbon dioxide and methane,” said Kolka, “Those greenhouse gases come out of these peat land ecosystems.”

“Lots of old carbon, lots of uncertainty of what happens to it, if in fact it were faced with warming at various levels,” said Hanson to a group during Wednesday’s open house.

It’s uncertainty that scientists hope to clear up as they spend the next ten years conducting the experiment.

The project is funded by the U.S. Department of Energy.

Applications, Dalton

Extrusion Die Heating

(Article reprinted courtesy of our partners at Dalton Electric Heating Company.)


Extrusion machines can be fitted with a variety of dies. A continuous sheet of plastic employs the use of a sheet die, sometimes called a hanger dies, due to the clothes hanger shape of the plastic channel to the extrusion lip of the die. The die must be heated to keep the plastic viscous and this is accomplished by cartridge heaters.




Heaters are installed from the back of the sheet die, extending toward the lip of the die where the plastic is released as a sheet. The Watt-Flex® cartridge heater has several distinct advantages over conventional cartridges. The hot tip feature of the Dalton heater gets more responsive heat to the end of the bore and the lip of the die for greater production control.


And the sheet die generally has a closed bore, sometimes with a small knock-out hole for stuck heater removal. The Watt-Flex heater will expand in the bore for better heat transfer and contract for ease of removal. Better performance and no seized heaters!



Charlie’s Smokehouse

In 2009 we received a call from a fellow who identified himself as “Charlie of Charlie’s smokehouse in Wisconsin”. Naturally, the first thing that came to mind was meat! It turns out that Charlie is the proprietor of “Charlie’s Smokehouse” located in Ellison Bay, Wisconsin on Lake Michigan and they smoke fish – not sausage – freshly caught from the deep blue waters of the Lake.



Charlie, like many owners of food processing plants, is paid a visit periodically by the FDA – in Charlie’s case, the food safety division of the Wisconsin Department of Agriculture. The Department inspects the facility and verifies that the company has their HAACP program in place and working. HAACP is an acronym for Hazard Analysis & Critical Control Points and is a management system in which food safety is addressed through the analysis and control of biological, chemical, and physical hazards from raw material production, procurement and handling, to manufacturing, distribution and consumption of the finished product. For more information on HAACP visit


Years ago, the manufacturer or processor would check the temperature in the smoke house and the cold storage facility with a bimetal thermometer and write the readings down on a piece of paper. Then along came circular or strip chart recorders. Recorders require some maintenance, including changing charts and pens daily or weekly. When Charlie called he was looking for a more “modern day” solution so we recommended the Madgetech Quadtemp2000 – a multi channel datalogger – which accepts up to four thermocouples simultaneously, records temperatures for weeks at a time and can be downloaded to a computer and displayed in an excel spreadsheet or emailed to the appropriate government agency, customer, etc. Within days Charlie had his new automated HAACP compatible temperature logging system up and running.



No more daily trips to the smokehouse and cooler to manually record the temperatures or fiddling with charts – it’s still running perfectly today. I know because I recently spoke with Charlie to order my smoked fish for the holidays. It is really tasty and I highly recommend it. I save some to make fish dip. Yum! Go to Charlie’s website and see for yourself!


Fishing With Thermocouples


At W. H. Cooke & Co., we get phone calls in regards to thermocouple applications from engineers, purchasing agents, maintenance folks, and in this particular case, a fisherman named Frank. This gentleman is a fisherman in the Great Lakes region and he told me that he has found that the fish like to swim below the surface of the water in a specific temperature range.


He was looking for a way to detect the temperature of the water where his hook will be. We designed a thermocouple for him that he could attach to his line, just above the hook. We used a 1/2” x 1/2” stainless steel hex nipple fitting to act as a sinker with a small probe exiting the front of the bore of the nipple. Water resistant epoxy was used to seal the front of the nipple as well as the back of the nipple where the waterproof Teflon leads exited. Back on the boat, we sold Frank an Extech TM100 that he could use to read the thermocouple.


Now, he lets out enough line from his rod until he hits the depth where he knows the fish are biting and reels them in. Frank is a 21st century fisherman and while we don’t expect that everyone is ready to attach a thermocouple to their line and cast out, perhaps we can help you with a different unique application. You dream it, we’ll make it.


Clean Room Application


A cGMP (Current Good Manufacturing Process) FDA compliant customer manufactures products for the pharmaceutical market and has a clean room in which he has to maintain a positive pressure in order to keep the area contaminant free.  He needed to be able to monitor this room to be sure his filters and fans were working properly at all times.  The clean room shown as room “2” below is the critical clean room so it is necessary to enter through room 1 to get to room 2 – both on positive pressure.


Clean Room


We selected a zero-center Series 2000 Dwyer Magnehelic® differential pressure gauge with an 0.25″ w.c. (water column) range either side of zero whichmakes an effective monitor for proper operation of the room pressurization system. In the example shown below, differential gauge B has its high pressure port open to room 2 and its low pressure port to room 1 – gauge A has its high pressure port open to room 1 and its low pressure port open to atmosphere. With the makeup air supply damper adjusted properly, room 2 will be a higher pressure than room 1 which is at higher than atmospheric pressure and both gauges will read positive. Should the air supply to room 2 be obstructed, gauge B will read negative. If the air supply fails entirely, both gauges will read zero. For even better security, a Series A3000 Photohelic® switch/gauge will provide automatic alarm or start-up of a backup system.





Custom “Tri-Controller” portable control system for pH, temperature, speed control.




In 1999 a research lab / pilot plant needed to control several parameters in area of their fume hoods with a portable control system that could be easily moved about.

A large beaker filled with the customer’s test solution needed to be heated with an electric mantle wrapped around the vessel, while the solution was being agitated with an over the side mixer and dosed with an acid solution to maintain a pH level. In addition, the heater was to be started up an hour or so prior to the Tech’s arrival in the morning so a timer was incorporated to bring the vessel up to temp at 6:00 am.

All of this equipment was to be in a stainless steel portable enclosure that would not take up a lot of workspace.

We first selected a ¼ din pH control and Timer and a 1/16 din temperature control to read and control the parameters. We then designed an enclosure with a sloping front and hinged cover that measured 18” x 10” x 10” and had a local sheet metal fabricator build 3 of them for the job. Holes were cut to accept the controls and then wired to 120 VAC receptacles that allowed the customer to plug in their 2 heating elements (top and bottom of vessel), their mixer and their acid dosing pump.

Additional receptacles were added to plug in the mixer and the acid dosing pump. A main on off power switch with circuit breaker and terminal strips were installed and the system wired. Quick disconnects were added for the enc pH sensor connection and dual RTD inputs (one for the temperature controller and the other for the pH controller for automatic temperature compensation. We also provided a connector for dual 4-20 milliamp outputs to send the temperature and pH readings to the customer’s recorder.

Wiring schematics and operating instructions were provided. If you are interested to know more about this system and application – read more here.

In 2014 the customer called and asked us to update these “Tri-controllers” and take advantage of more modern instruments on the market today. Instead of 3 portable systems this time, they wanted two portables and one fixed system that could be mounted near the fume hood with the addition of a remote digital display for the pH portion of the system. They requested that we utilize some of the original equipment and modify the functionality of the system as follows:

The two portable systems retained the original pH and temperature controls while the start up timer was removed (no longer necessary) and a ¼ din data logger was added. The data logger records the pH, temperature, mixer motor speed and torque. Necessary quick disconnects were added for all input signals from the various sensor/transmitters and a panel mount USB connector for downloading the data logger records to a thumb drive when desired.

The permanent system was installed in a 14” x 12” x 8” fiberglass raised face enclosure with the same control scheme but with the addition of a remote Precision Digital panel meter that would be visible at the customer’s eye level.



Front View


Side View









submitted by Wayne Cooke Sr.


Bore seizures are non existent

A  major aluminum extrusion manufacturer was experiencing a high rate failure rate of electric cartridge heaters used in their process.  The heaters were seizing in the “pusher nose” –  the ram used to push the heated billet through the die.  These “nose heaters” must be kept hot to avoid pulling heat from the billet during the extrusion process.

When the heaters seize, they must be drilled out and the heater holes reamed to smooth out the bore which becomes damaged during the drilling and extraction process. When a new heater is inserted they now had a sloppy fit resulting in poor heat transfer from heater to pusher nose with the heaters sometime falling out.  Needless to say, they were experiencing poor performance and high power usage because the heaters had to run hotter and longer to produce the necessary heat required.

The customer wanted a solution and our salesman suggested using a unique cartridge heater offered by one of our principals Dalton Electric Heating Co., Inc. The “split sheath” cartridges expand up to .020″ over their original diameter – enough to take up the slop created by repeated seizures and drill outs of the old conventional design heaters.  The customer placed a small test order for heaters and we waited for the feedback.  So did we solve the problem for the customer?

Yes,  Bore seizures are non existent since switching to the Dalton heaters resulting in:

1. Reduction in replacement cartridge heater purchases
2. Huge savings in machine shop time drilling out seized heaters
3. Reduced Maintenance time pulling rams for service
4. Reduced power consumption.  How much.  We can’t say for sure because the customer does not measure or keep records of electric power usage by department but we typically see savings of upwards of 20%

This is an example of how we may be able to help you with a production or Maintenance problem in your plant.  Please take a moment to watch the video of the benefits of Dalton Electric Heaters.

Incidentally – we have received several subsequent orders for the Dalton split sheath cartridges from a very happy customer.


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