New Products

Integrators
(DC to Frequency Converters)

Brand-new Models JH7500 & JH7501 integrators convert a DC measurement signal (voltage or current) to a proportional frequency. JH7500 is the general-purpose version. JH7501 operates at low pulse rates - its output is a set of relay contacts that 'click' at the output pulse rate.

Integrator - why the name?

The original - and still common - application is to totalize, or "integrate" flow measurements. A signal from a flowmeter represents flow rate (such as gallons per minute). Each output pulse represents a fixed quantity (such as a gallon, fraction of a gallon or number of gallons). The pulses are fed to a counter. The faster the flow the faster the pulses, so the total flow may be found by reading the counter. Similarly, if the input represents instantaneous power (kilowatts) the total represents power usage (kilowatt-hours).

More modern applications include signal conversion (convert a DC measurement signal to frequency for a PLC's input) and tone telemetry (transmit the converted frequency over a distance, then convert it back to DC at the receiving eng. JH Technology offers frequency to DC converters (also called frequency input transmitters) to perform the receiving end conversion.

For product details click:
JH7500/JH7501 Integrators (DC to Frequency Converters
JH7010I Frequency to DC Converter (Plug-in style, fixed range)
JH7580 Frequency to DC Converter (Plug-in style, user rangeable)
JH5700 Frequency to DC Converter (DIN-rail style, fixed range)

Our web site: http://www.jhtechnology.com/

New from JH Technology

FAST Response!

Transmitters with 1 millisecond response time.

Last year we spotlighted a new design we'd done for a customer needing a quantity of fast-response transmitters. We've now turned it into a standard product offering.

Available on most of our DIN-rail transmitters (JH5000 Series), Option HS output is approximately complete (95% response) in 0.001 seconds. It is not available on AC input or frequency input transmitters, as these require filtering to function properly.

Frequency response is 3dB down (0.707 times the DC gain) at approximately 600 Hz.

Faster (or slower) available - contact us!

Link to Fast Response Process Transmitters

Signal Conditioners & Process Transmitters (link to our web site): www.jhtechnology.com/    

e-mail jhtek@jhtechnology.com

Custom Designs

A Very Special Special

A well-known company needed to duplicate a thermocouple alarm they had bought from Action Instruments decades ago. Action was no longer able to provide it so they turned to us.

Action's original "Action Pak" line (Action's trademark) once included alarm modules with extra options such as retransmitting outputs and remote setpoint inputs. 20-pin headers (pin bases) were required to provide the extra connections. As far as we are aware these headers are no longer available.

Our customer's requirement was a nonstandard version of one of those alarms. We replied that we could provide the same function but with a different connection arrangement. This was not acceptable - it was for a nuclear power application and they could not vary the system design. Only one piece, but they were willing to pay for it.

Once again we got lucky. In 1995 we had purchased some 20 pin headers for another customer's need and had a handful left. Our customer bought one (couldn't convince them to buy a spare) - even sent an inspector to Florida to do a source inspection. That was 2008. In 2009 they again bought one and just now ordered two more! Possible future problem - after this order we have only five headers left.

(Note: We do not sell nuclear-approved products. This alarm was sold as "standard commercial quality" for a noncritical application.)

Technical detail: the custom alarm module has two retransmitting 0-1V analog outputs, one proportional to temperature and the other proportional to the setpoint. Our customer was able to supply us with Action's specifications and we designed it to be functionally identical. Here's the functional diagram.

If you have special requirements let us know. Phone (941) 927-0300 or toll-free (800) 808-0300.

E-mail jhtek@jhtechnology.com.

Link to our page on Custom & Special Signal Conditioners.

Signal Conditioners, General - our web site: http://www.jhtechnology.com/

Economic Upturn?

Maybe. We're seeing signs.

After a best-ever 2008 we saw about a 25% downturn in 2009. 2010 started off equally bad, maybe even worse. Then, April & May were strong - above our 2008 average. We're cautious, though. The two months were helped by unusually large orders from four customers. So - cautiously optimistic!

Another sign - not necessarily good - component shortages and lead times are increasing rapidly - up to 20 weeks. So far we're able to cope, as most of our parts are available from multiple sources.

Such problems aside, let's hope the improvement continues.

Application Note

Detect Thermocouple Failure Without Upsetting the Process

One from the archives. Our customer needed to alarm on thermocouple failure without shutting down the process.

Thermocouple instruments commonly include upscale burnout indication. If the thermocouple breaks or fails open-circuit the instrument's output goes high, just as if the temperature had gone out of control. This often is used to insure failsafe failure, shutting the process down and sounding an alarm.

Our customer, a utility, needed an overtemperature shutdown on a monitored water temperature. They also wanted to trip an alarm upon thermocouple failure but without interrupting the process. We were able to suggest a simple dual-trip alarm setup to do this.

Our thermocouple instruments, like most others, offer a downscale burnout option. (Thermcouple failure causes the output to go low instead of high.) Using a dual-trip alarm, we set trip #1 for HI trip and trip #2 for LO. The HI trip, of course, was used to shut the process down on excessive temperature. The LO trip was set below freezing. Its relay would trip when the thermocouple failed but never under normal operation.

For the full application note, click here.

Our web site - Signal Conditioners, Process Transmitters: http://www.jhtechnology.com/

E-mail: jhtek@jhtechnology.com

Export Sales

Helping the balance of trade -

Although the majority of our sales are within the US we welcome interntional orders. In the past two weeks we've shipped:

• 25 more pieces of a custom assembly (4-input load cell amplifier) for our good OEM customer in Sweden. They buy a few hundred per year - we have an open order for 50 more right now.
• 30 more JH4380W rangeable DC transmitters - specials - with extended temperature ICs to guarantee operation to minus 40 degrees. Although shipped to a US customer, they will be using them in systems exported to Russia. A repeat order - they ordered 54 last year.
• 6 transmitters to an overseas distributor.

 We're grateful for all orders, foreign or domestic.

Current Booster

THE BOOSTER!

Well, ok, not that booster!

Another "rush" special - to boost the current drive from a voltage signal. Our customer needed -10 to +10 volts to drive a 50 milliamp load. The voltage output from their control signal could supply only a fraction of that, so they needed an output-equals-input driver or current booster. They called us.

• 
  
  Additional needs: "ASAP - yesterday if possible" because they had just discovered the system problem.
• 
  
  Very high accuracy for their test application.

We got lucky. Years ago we solved another customer's high-current requirement by designing a custom circuit board. The requirements were different, but we were able to use that board to assemble the required circuit. It so happened that we had three of those boards left. Our customer needed four, but two could wait. We received the order March 22, shipped the first two March 23 and ordered a few more boards from a quick-turnaround service.

Accuracy? We guaranteed +/-3mV on a 20 volt wide span (+/-0.015% of range).

The customer has now asked us to quote on an 8-channel version.

This one isn't on our web site, but you can see examples of other special & custom signal conditioners at www.jhtechnology.com/customs.