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.

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  Additional needs: "ASAP - yesterday if possible" because they had just discovered the system problem.
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  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.

Two Wire Transmitters

Some People Like

Trimpots!

We recently picked up a new customer who ordered a few of our 2-wire thermocouple transmitters. This customer sells thermocouples and other temperature probes, and the manufacturer they represent also offers transmitters from a well-knows European company.

Why did they buy ours? The European brand is computer-ranged. The end user wanted to be able to adjust calibration without needing a computer set-up. So, they bought our "old fashion analog" fixed range Model JH220 - complete with trimpots!

This is at least the second time this has happened. Another of our customers, a temperature sensor manufacturer, ran into exactly the same objection years ago and regularly offers our transmitters even though they also handle the European brand.

Do you need to change ranges but still like trimpots? Model JH225 (shown) adds switches that let you recalibrate to almost any practical range for thermocouple types J, K and T. (You do need a calibration source.) We also offer similar transmitters for RTD (resistance thermometer) sensors.

Links:
Model JH220, thermocouple 2-wire transmitter, fixed range (factory set)
Model JH225, thermocouple 2-wire transmitter, user-rangeable
Model JH240, RTD (resistance thermometer) 2-wire transmitter, fixed range
Model JH245, RTD 2-wire transmitter, user-rangeable

All 2-Wire Transmitters

Simple Specials

Standard Product, Nonstandard Connections

Our OEM customer needed a fully compatible replacement for a thermocouple alarm module they once bought from England. Our Model JH1200 plug-in thermcouple alarm filled the bill, except the pin connections were different.

The answer was simple - take our standard product, unsolder the internal wires from the pins and rewire them to be the same as the British product. And, since the the connections to the thermocouple were changed, we also needed to relocate the temperature sensor used for cold junction compensation.

One more step - we made a simple adapter to allow the converted alarm module to plug into our standard production test and burn-in fixtures.

This customer buys only one or a few at a time, but they've become a regular for several years.

Links: Process Alarms
JH1200 Thermocouple Alarm
Custom & Special Signal Conditioners

Simple Specials

SPECIAL ORDER -

SUM THREE UNEQUAL FLOWS

Flow #1: Full Scale (20mA) = 1.75 MGD (Million Gallons per Day)

Flow #2: Full Scale (20mA) = 22 MGD

Flow #3: Full Scale (20mA) = 1.04 MGD

Module Output: Full Scale (20mA) = 24.79 MGD

Something we do all the time - modify our products to meet out-of-the-ordinary needs. In this case the customer needed to add signals from three flowmeters, each having a different scale factor.

A bit of engineering calculation, followed by the selection of a few precisely-measured input resistors, did the trick.

One piece order. Turn-around time - four days from order entry to shipment.

Product Spotlight

Two-Wire Transmitter -

Potentiometer Input

Our "sleeper" product - not new and, you would think, not particularly exciting, but people keep finding it and buying it, so we thought we'd feature it.

Pretty simple - takes a potentiometer input and converts it to a 4-20mA two-wire (loop-powered) output. Quite honestly, it was an afterthought when we designed our temperature (RTD and thermocouple) two wire transmitters years ago. Laying out the circuit board so it could also be assembled for potentiometer input was easy, so we included it.

Sells better than we ever expected. Just this month we picked up two new customers for it. The applications can be anything that needs to convert position to an electrical signal. A couple applications - level measurement and boat throttle position. The level measurement application uses a probe with series of resistors and reed switches, activated by a magnetic float.

Links: Model JH250 Potentiometer Transmitter
Other Two-Wire Transmitters
Our web site - http://www.jhtechnology.com/

Can You Help????

Here's a question we can't help with. Can you?

The other day a fellow called to ask if we could build a custom dashboard panel for his car. We've had two similar calls recently - at least one of them was from a man who was converting an older model to electric power. (He wanted it to look as much like the original dashboard as posssible.) All of them had seen from our web site that we can design panels and minisystems.

This is outside our area of expertise. Industrial control panels, yes. Automotive, no. We'd need to know the size, shape, mounting arrangements etc of the car's dashboard and the electronic details of the car's sensors.

I thought I'd post this for our readers. Can you help, or do you know anyone who can?

Product Spotlight

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Field Mount Enclosures

In our last posting (December 26,2009) we highlighted our FDT5000 Series field mount transmitters with displays. If you don't need a display you can mount any of our plug-in transmitters and alarms in the two enclosures featured here.

NEMA-4X Rated Enclosure

Splashproof & corrosion resistant, it includes the mating socket. It is normally sold without an opening or conduit connection as the installer usually prefers to determine this detail. If you would like us to provide this please e-mail jhtek@jhtechnology.com or call 941-927-0300 (in the US, toll-free 800-808-0300) us with your requirements.

Part #ENCL-1-8 with 8-pin socket, or ENCL-1-11 with 11-pin socket.

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Explosion Proof Enclosure

This is a Hubbell-Killark enclosure, modified by adding an 8- or 11-pin socket. UL, CSA and Factory Mutual approvals include Class 1, Div 1 & 2, Groups A, B, C & D when properly installed. A neoprene o-ring assures water-resistance per NEMA 4/IP66. Two 3/4 inch-14 NPT threaded conduit openings are provided.

Part #ENCL-EX1-8 with 8-pin socket, or ENCL-EX1-11 with 11-pin socket.