Signal Conditioning Products

In business since 1994, with over 30 years of instrumentation design experience, JH Technology is ready to meet your needs. We're small - we're responsive - we're engineering-driven and enjoy a challenge.

For products designed to your unique requirements or to solve unusual application - contact us. We'll work with you, engineer-to-engineer, to create a solution.

Most of our product designs are modular - separate input, output and power subassemblies. These assemblies can be interchanged and, usually, easily modified.

Often, your needs can be met by simple internal modifications - change a resistor or two, cut a circuit trace, add a jumper etc. Such modifications have little impact on price or delivery, even on one-piece orders.

To see examples of specials we've done, click here.

JH Technology's measurement expertise extends beyond our catalog product line, including such areas as flow, conductivity, pH, LVDTs and humidity. We're able to modify our standard product designs, to create short-run prototypes or design, tool and run full custom designs. And, we usually won't require a major commitment. For projects that fit our overall expertise we often can do the job with only modest engineering charges and production quantities.

For OEMs we can do anything from private-labeling our standard product to complete custom designs.

Click here for examples of custom work we've done.

Sometimes you need just a module or two in a small panel or NEMA enclosure, maybe with a readout or control function added. We'll combine our products with others to meet your unique system requirements. Click here for some examples.

There's nothing "standard" about our specials. We've quoted over 200 so far. Many have been sold repeatedly - some to multiple customers, others as OEM designs. Others were one-time, one-piece orders to meet specific needs.

Examples follow. Whether your need is on this list or is new and different, contact us to discuss your requirements.
 

	More Filtering. Our instruments normally include modest filtering to minimize AC and noise pickup. Some systems need heavy filtering to smooth or average noisy or varying signals. We've added increased filtering - both fixed and user-adjustable - providing time constants up to 30 seconds.
	Less Filtering - Fast Response. Sometimes filtering must be reduced or eliminated to monitor rapidly-changing signals. Applications have included measuring voltage and pressure transients, rapid temperature changes and projectile impact force.
	Fast Rise, Slow Decay. To capture the peaks of transient signals we've added fast-rise, slow-decay response. For regularly repeating periodic signals the output approximates the peak value. For one-time pulses the slow decay (3 second time constant) allows the peak to be observed or captured.
	Delayed Alarm Trip. To avoid false trips due to momentary transients, the alarm will not trip unless the signal remains out-of-bounds longer than the delay time. We've added fixed and adjustable delays up to 30 seconds.
	Wide Adjustment Range. Most of our fixed-range transmitters provide fine adjustment of zero and span, about +/-15%. Some applications need more. We've done a number of modifications to allow wider zero, span or both. The tradeoff - a reduction in adjustment resolution, making it more difficult to adjust to 0.1% or better.
	Remote Adjustments. We've replaced the built-in trimpots with remote adjustments for zero, span and/or alarm trip points.
	Nonstandard Input Ranges. Our standard catalog capabilities allow a wide variety of range possibilities but sometimes people need more - or less.  We've modified instruments to allow inputs up to 600 volts AC and DC, up to 10 amps and down to just a few millivolts.  We've also made changes to accept lower-than-standard temperature ranges.
	Nonstandard Output Ranges. Some applications need outputs beyond our standard catalog capabilities. We've provided 10-50mA and beyond, and voltages to plus or minus 25V. We've also provided output spans below our standard minimums of 1 volt or 1 mA.
	Max/Min Output Limiters. Most applications want to know when an input goes over- or under-range. Some, however, need firm limits to avoid false alarms or overdriving A/D converters or receiving instruments. We've added circuitry to limit both overrange and underrange outputs.
	Unique Math Functions. Our standard products provide add, subtract, multiply and divide functions. Square and square root, although no longer in our catalog, are still available. We've also provided 6-input summers (our standard limit is 4), unequal input ranges on math units, absolute value, absolute value subtractors and a summer with an adjustable scale factor on one input. And we've even built an AxB/C function.
	Contact Closure (On-Off) Inputs. In one application we modified our single alarm trip to trip upon contact closure and reset when the contact opened. In another we provided a transmitter whose output toggled between two preset values, one for open, another for closed.
	Increased Ambient Temperature Range. We've provided extended operating range by assembling otherwise-standard products using extended-temperature ICs.
	High Input Impedance. We've modified standard transmitters (voltage input) for 10 and 20 megohm impedance and built a custom buffer with 100 megohm impedance.
	Nonstandard Pin or Terminal Connections. Occasionally, people need replacements for plug-in modules having pin connections different from ours. No problem -we'll rewire to your needs.
	Restricted Access to Adjustments. Our trimpot adjustments normally are accessible. When you need to restrict unauthorized access we'll cover them. Recalibration requires opening the enclosure.
	Frequency Input Transmitter with Unique Functions. To work with a specific Brooks Optoturbine flowmeter we needed to supply regulated 8.2 V to the turbine and receive current pulses varying between 1.2 and 2.1 mA.  A modified JH7010 frequency transmitter produced a 4-20 mA flow rate output.
	Transmitter for Two Input Ranges. The customer needed true-RMS measurement on two different high-voltage ranges. We modified our circuit and added connections such that one set of input terminals provided a 0-250Vac range; the other, 0-480V.
	Alarm with Unique Functions. This OEM special provided a single-trip alarm with 0-5 volt retransmitting output, fast response and delayed reset.
	4-20mA Output Compatible with 120Vdc Loop Power. Most of our transmitters offer a Loop Powered Output option (LPO). This allows our AC-powered transmitters to be safely connected to PLCs and other systems whose inputs include 24V loop excitation. One customer's unique application required 120Vdc loop excitation, not 24V. We did it.
	RTD Alarm with Adjustable Excitation Current (30mA max). A very unique test application using a 500 ohm platinum RTD (resistance thermometer). Normally the RTD current is kept very low to minimize self-heating errors. This test application, though, needed the excitation to be adjustable from 1 to 30mAdc.

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Here are some custom designs we've done. To discuss your unique needs, please contact us.

	4-Input Load Cell Amplifier. A major new design for an OEM customer. This transmitter board provides an output proportional to the sum of four load cells. Unlike many other devices, it provides four individual input channels which may be balanced (offset and gain adjusted) without any cross-channel interaction. Its physical and electrical design is unique and exclusive to this customer, but we can design others to meet your requirements.
	Low-Cost Thermocouple Amplifier. A temperature sensor manufacturer needed a small, low-cost thermocouple amplifier in OEM quantities for a major project. We designed and built a simple board assembly per their specifications.
	High-Current Driver. This plug-in transmitter module provides plus and minus voltage or current outputs at up to 250mA. We're in the process of converting this to a standard product, JH4010DR.
	Custom Curve-Matching Transmitters. Originally designed for a specific application, we have the capability to match curves using a 5 line-segment approximation. We've assigned it the generic Model No. JH4155 and designed several others since, but each is unique.
	Adjustable Filtering. Designed for one customer and since sold to others, this design provides analog filtering with an adjustable time constant (63% response time) from 0.1 to 30 seconds. Originally designated as a special, we now call it Model JH4580.
	Miniature Signal Filter. The customer needed to filter a number of industrial process signals and wanted as small an enclosure as possible. We designed a DC-powered filter in our two-wire transmitter enclosure. We now make it available to others as Model JH10185.
	Differential RTD Input Transmitter. Two RTD (resistance thermometer) inputs. The transmitter's output is proportional to their difference. Narrow spans only.
	Thermistor Inputs. We once included thermistor-input transmitters and alarms in our standard product line but removed them for lack of sales. Sure enough - shortly after we removed them we had two customers needing them - one on a repeat basis. We also can handle inputs from integrated circuit temperature sensors.
	Tachometer Pulse Amplifier. This small, low-cost DC powered pulse amplifier was designed for an OEM customer but is available to others. Model JH10159.
	Pulse Isolator/Conditioner. This high-end, high-capability product is usable with pulse amplitudes as low as 10mV and as high as 250Vac rms, and with frequencies up to 30kHz. Input/output isolation is standard. We're in the process of turning this into a standard product - Model JH10205
	Phase Imbalance Detector. Not quite what it sounds like. Our customer needed to compare the signals coming from three current transformers (CTs) having 4-20mAdc outputs. The application was, three banks of heating lamps. If one lamp burned out the phase currents would become unequal. Our instrument compared the three and tripped a relay if they became imbalanced by more than a preset percentage.
	Miniature Differential Thermocouple Amplifier. The application - monitor aspects of rocket performance during launch. Hardly "industrial", these flew on commercial satellite-launch rockets. This one-time project was designed to meet size, temperature and fast response requirements. We located a small die-cast enclosure, laid out a custom board and added a miniature connector per the user's requirements.
	Tone Telemetry Encoder. Translates high/low input switch contacts to a high/low tone for transmission over a leased telephone line. The application - remote monitoring of sewer lift stations. Originally designed by City of Tampa technicians, we cleaned it up and repackaged it as a plug-in module and now build it for them. Model JH10120 - available for general sale.
	High Impedance Electrode Buffer. A precision unity-gain voltage buffer with 100 megohms input impedance. The application - measurements from an electrochemical sensor. Available for general sale - Model JH10061
	12Vac "Power Supply". Probably our simplest ever. The customer needed a 115Vac to 12Vac transformer housed as a plug-in module. We did it.

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What is a Minisystem? It's our name for a small collection of instruments and controls - ours or others - to meet needs a single instrument can't handle. Some might be a simple as a standard product packaged differently. Others might combine a transmitter with a display, controller, relay, SCR or one or more pushbuttons to create a small stand-alone control system, maybe in a NEMA enclosure or small panel. Often a Minisystem may be a more economical solution to a one-time need than a full-blown custom design.

Here's a list. So far we've only done a few, but we'd like to add yours. Contact us with your requirements.

	Gas Flow Computation System. Our customer was using standard turbine flowmeters to measure volumetric flow but wished to upgrade to true mass flow measurement. By adding temperature and pressure sensors to the gas lines we were able to use our frequency-to-dc and computational modules to meet the need. Five modules were mounted on a panel inside a NEMA-4 field mount enclosure. Not inexpensive, but we provided significant savings compared to replacing large flowmeters.  Click here for more details.
	Quad Valve Controller. Four position-feedback valve controllers in a single panel-mount enclosure. Digital "Knobpots" on the front panel provide precise setpoints.
	Manual Control Source. Nothing more than our JH4003 potentiometer-input transmitter, a pot and a digital readout mounted in a desktop enclosure. The user needed it to manually adjust a remote damper valve.
	Hazardous Temperature Alert. A processing plant needed an on-site warning of possible overtemperature danger. We packaged our standard Model JH1200 Thermocouple Alarm together with two large LED lamps in a NEMA-4X enclosure.
	Custom Dual Display. Our customer needed an outdoor display for two 2-wire transmitters, one reading pressure, the other, temperature. The display also needed to provide power to the transmitters. We mounted two commercially-available LCD displays plus supply circuitry in our NEMA-4X FT5000 Series transmitter enclosure.

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We're in business to meet your needs. Contact us to solve your unique measurement problems.