Analog Input Products

Analog Input Products

AMPLIFY AND MULTIPLEX INPUT SIGNALS FROM A VARIETY OF SOURCES

Analog input boards are useful for measuring variably changing conditions in the real world. When we want to measure these variably changing conditions, we need analog inputs to convert these changing real world conditions to changing electrical quantities. For example, monitoring the temperature inside a wood kiln, or the water pressure on the output of a pump, or the heart rate of a medical patient. In each of these cases, you can use one of our analog input devices to convert the electrical data from a sensor or transducer into binary data that can then be used by your computer. The device that converts this data is known as an analog to digital converter (abbreviated ADC, A/D, or A to D). An analog input is a measurable electrical signal with a defined range. The analog input changes continuously in a definable manner in relation to the measured property. This data is very useful for process monitoring, process control, or simple monitoring / data collection and acquisition. ACCES’ analog input boards amplify and multiplex input signals from thermocouples, strain gauges, accelerometers, photo sensors, flowmeters, RTDs, thermistors, voltage sources, millivolt sources, and current sources, just to name a few.

There are basically three types of analog input signals used to measure these conditions. They are voltage, current, and resistance.

If voltage mode is used, analog input connections can be either single-ended or differential. Low per-channel cost is a major advantage of using single-ended inputs because only one multiplexer switch is needed per channel and there is less system wiring. Single-ended inputs all share a common return or ground line. The measurement is the difference between the signal and the ground. Only the “high” signal wires are connected through the amplifier and multiplexer. The “low” wires return through the system ground connections. That is, both the signal source and the amplifier are referenced to ground. This arrangement works fine as long as the ground potential difference is very small. However, if there is a large difference in ground potential, extraneous currents can flow and generate errors. This is called a “ground loop”. Ground potential differences (ground loops) can cause larger interference problems than electromagnetic fields. Ground loops occur if the sensors are tied to a local ground. That local ground can be many volts different from the ground potential at the receiving circuit. Single-ended measurements are also more susceptible to noise than differential measurements due to differences in the signal paths and the tendency to pick up surrounding electrical activity. With single-ended inputs you have no way of distinguishing between the signal and the noise.

To avoid this problem, a differential-input connection can be used with an amplifier that has a high common mode rejection ratio. A differential arrangement connects both ends of the signal source to the inverting and non-inverting inputs of the amplifier. Measurement is the difference in voltage between the input and the reference, which helps to reduce noise and any voltage that is common to both wires. Twisting wires together will ensure that any noise picked up will be the same for each wire. In this way, voltage due to ground loops appears as a common mode voltage and can be rejected by the common-mode-rejection properties of the amplifier. An instrumentation type amplifier (rather than a simple operational amplifier) is required and two multiplexer switches are required per channel. An obvious disadvantage of differential inputs is that you need twice as many wires, so you can connect only half the number of signals, compared to single-ended inputs.

If you have signals larger than 1V, short signal wires, and close together signal sources, single-ended inputs should be fine. If your application falls outside these boundaries, differential inputs would be the wise choice.

In industrial applications, where wiring can be very long, it is common to use “current transmitters”; i.e., devices located at or near the transducer which convert the sensor output to an analog current signal (e.g. 4 to 20 mA). Current signals are sometimes used because they are relatively immune to errors such as induced noise and voltage drops due to lead resistance. and have become a de facto standard for critical process control measurements. Another plus is that it saves money due to reduced wiring cost. Current mode operation is somewhat susceptible to magnetically-induced errors. The simplest solution is to use twisted-pair signal lines and to keep those lines remote from power lines or other sources of magnetic induction. Also, at the receiving circuit, the signal usually must be converted into a voltage and level-shifted to a zero-based range so that it can be digitized using the full input capability of the digitizer.

Resistance measurement is most commonly associated with direct inputs from temperature sensing devices, such as thermistors and resistance temperature detectors (RTDs). RTDs are temperature sensors that exploit the predictable change in electrical resistance of some materials with changing temperature. They are slowly replacing the use of thermocouples in many industrial applications below 600°C, due to higher accuracy and repeatability. Thermistors are widely used as inrush current limiters, temperature sensors, self-resetting overcurrent protectors, and self-regulating heating elements. Thermistors differ from RTDs in that the material used in a thermistor is generally a ceramic or polymer, while RTDs use pure metals. The temperature response is also different; RTDs are useful over larger temperature ranges, while thermistors typically achieve a higher precision within a limited temperature range (usually -90°C to 130°C).

A wide range of flexible signal conditioning types per channel are also offered. These include options such as RC filters on each input, voltage dividers on each input, 4-20mA current inputs, thermocouples (temp sensor for cold junction), RTD measurement, as well as bridge completion.

For applications requiring analog inputs only, a line of cost efficient USB products offers all of the features described above except no analog outputs are included.

Signal conditioning is an essential requirement in many applications and systems which demand accurate and precise measurements. Signal conditioning circuits convert one type of electronic signal into another type of signal that can be used to improve and enhance the data acquisition system and application. Sometimes the data acquisition card that you plug into the computer provides necessary conditioning; sometimes that signal conditioning must be done external to the computer. In general, signal conditioning consists of amplification, isolation, filtering, sensor excitation, cold-junction compensation and more.

Signal inputs accepted by our signal conditioners include DC voltage/current and AC voltage/current. Sensor inputs can be accelerometer, thermocouple, thermistor, resistance thermometer (RTDs), strain gauge or bridge, and LVDT/RVDTs. Signal conditioned outputs include voltage, current, frequency, relay, isolation, and more.

ACCES offers a wide variety of external signal conditioning products which include analog, digital, and serial signal conditioning. Sometimes the data acquisition product you plug into the computer provides the necessary conditioning; and sometimes that signal conditioning must be done external to the computer.

Click the following wikipedia links to learn more about analog inputs, signal conditioning and data acquisition in general.

PCI Express Mini

Model# of InputsRes BIP RGSpeedLearn Morehf:att:pa_addr-cfghf:att:pa_autocalhf:att:pa_baudhf:att:pa_bip-rghf:att:pa_bip-rg-inputhf:att:pa_buffhf:att:pa_bus-connhf:att:pa_cable-lengthhf:att:pa_cable-typehf:att:pa_connectorhf:att:pa_coshf:att:pa_counter-resolutionhf:att:pa_counter-typehf:att:pa_countershf:att:pa_digital-i-ohf:att:pa_fifohf:att:pa_four20mahf:att:pa_inputshf:att:pa_isolationhf:att:pa_kithf:att:pa_lrg-fifohf:att:pa_on-board-calhf:att:pa_optoshf:att:pa_outputshf:att:pa_pcie-laneshf:att:pa_pcie-x1-expansionhf:att:pa_proghf:att:pa_prot-cfghf:att:pa_quad-inputshf:att:pa_receiver-typehf:att:pa_relayhf:att:pa_reshf:att:pa_res-inputhf:att:pa_rs-232hf:att:pa_rs-422hf:att:pa_rs-485hf:att:pa_speedhf:att:pa_uni-rghf:att:pa_uni-rg-inputhf:att:pa_xt
mPCIe-ADIO16-8F8 SE, 4 Diff1671MHzLearn More3716-i-ono8-se-4-diff416161mhz2yes
mPCIe-ADIO16-8A8 SE, 4 Diff167500kHzLearn More3716-i-ono8-se-4-diff41616500khz2yes
mPCIe-ADIO16-8E8 SE, 4 Diff167250kHzLearn More3716-i-ono8-se-4-diff41616250khz2yes
mPCIe-ADI16-8F8 SE, 4 Diff1671MHzLearn More3716-i-ono8-se-4-diff63416161mhz2yes
mPCIe-ADI16-8A8 SE, 4 Diff167500kHzLearn More3716-i-ono8-se-4-diff6341616500khz2yes
mPCIe-ADI16-8E8 SE, 4 Diff167250kHzLearn More3716-i-ono8-se-4-diff6341616250khz2yes
mPCIe-ADIO12-8A8 SE, 4 Diff127500kHzLearn More3716-i-ono8-se-4-diff41612500khz2yes
mPCIe-ADIO12-88 SE, 4 Diff127250kHzLearn More3716-i-ono8-se-4-diff41612250khz2yes
mPCIe-ADIO12-8E8 SE, 4 Diff127100kHzLearn More3716-i-ono8-se-4-diff41612100khz2yes
mPCIe-ADI12-8A8 SE, 4 Diff127500kHzLearn More3716-i-ono8-se-4-diff6341612500khz2yes
mPCIe-ADI12-88 SE, 4 Diff127250kHzLearn More3716-i-ono8-se-4-diff6341612250khz2yes
mPCIe-ADI12-8E8 SE, 4 Diff127100kHzLearn More3716-i-ono8-se-4-diff6341612100khz2yes
mPCIe-AIO16-16F16 SE, 8 DIF1671MHz ×2Learn More372-i-ono16-se-8-dif416161mhz-x22550yes
mPCIe-AIO16-16A16 SE, 8 DIF167500kHzLearn More372-i-ono16-se-8-dif41616500khz2550yes
mPCIe-AIO16-16E16 SE, 8 DIF167250kHzLearn More372-i-ono16-se-8-dif41616250khz2550yes
mPCIe-AI16-16F16 SE, 8 DIF1671MHz ×2Learn More372-i-ono16-se-8-dif63416161mhz-x22550yes
mPCIe-AI16-16A16 SE, 8 DIF167500kHzLearn More372-i-ono16-se-8-dif6341616500khz2550yes
mPCIe-AI16-16E16 SE, 8 DIF167250kHzLearn More372-i-ono16-se-8-dif6341616250khz2550yes
mPCIe-AIO12-16A16 SE, 8 DIF127500kHzLearn More372-i-ono16-se-8-dif41612500khz2550yes
mPCIe-AIO12-1616 SE, 8 DIF127250kHzLearn More372-i-ono16-se-8-dif41612250khz2550yes
mPCIe-AIO12-16E16 SE, 8 DIF127100kHzLearn More372-i-ono16-se-8-dif41612100khz2550yes
mPCIe-AI12-16A16 SE, 8 DIF127500kHzLearn More372-i-ono16-se-8-dif6341612500khz2550yes
mPCIe-AI12-1616 SE, 8 DIF127250kHzLearn More372-i-ono16-se-8-dif6341612250khz2550yes
mPCIe-AI12-16E16 SE, 8 DIF127100kHzLearn More372-i-ono16-se-8-dif6341612100khz2550yes

USB

Model# of InputsRes BIP RGUni RGSpeedFIFOAutocalLearn Morehf:att:pa_addr-cfghf:att:pa_autocalhf:att:pa_baudhf:att:pa_bip-rghf:att:pa_bip-rg-inputhf:att:pa_buffhf:att:pa_bus-connhf:att:pa_cable-lengthhf:att:pa_cable-typehf:att:pa_connectorhf:att:pa_coshf:att:pa_counter-resolutionhf:att:pa_counter-typehf:att:pa_countershf:att:pa_digital-i-ohf:att:pa_fifohf:att:pa_four20mahf:att:pa_inputshf:att:pa_isolationhf:att:pa_kithf:att:pa_lrg-fifohf:att:pa_on-board-calhf:att:pa_optoshf:att:pa_outputshf:att:pa_pcie-laneshf:att:pa_pcie-x1-expansionhf:att:pa_proghf:att:pa_prot-cfghf:att:pa_quad-inputshf:att:pa_receiver-typehf:att:pa_relayhf:att:pa_reshf:att:pa_res-inputhf:att:pa_rs-232hf:att:pa_rs-422hf:att:pa_rs-485hf:att:pa_speedhf:att:pa_uni-rghf:att:pa_uni-rg-inputhf:att:pa_xt
USB-AI16-2A216441MHz ×2YesNoLearn Moreno44-in-4-outyes2634161mhz-x24yes
USB-AIO16-16F16 SE, 8 DIF16441MHzYesYesLearn Moreyes1416-io-8-8yes16-se-8-dif2-or-416161mhz14yes
USB-AIO16-16A16 SE, 8 DIF1644500kHzYesYesLearn Moreyes1416-io-8-8yes16-se-8-dif2-or-41616500khz14yes
USB-AIO16-16E16 SE, 8 DIF1644250kHzYesRefsLearn Morerefs1416-io-8-8yes16-se-8-dif2-or-41616250khz14yes
USB-AI16-16F16 SE, 8 DIF16441MHzYesYesLearn Moreyes1416-io-8-8yes16-se-8-dif63416161mhz14yes
USB-AI16-16A16 SE, 8 DIF1644500kHzYesYesLearn Moreyes1416-io-8-8yes16-se-8-dif6341616500khz14yes
USB-AI16-16E16 SE, 8 DIF1644250kHzYesRefsLearn Morerefs1416-io-8-8yes16-se-8-dif6341616250khz14yes
USB-AIO12-16A16 SE, 8 DIF1244500kHzYesYesLearn Moreyes1416-io-8-8yes16-se-8-dif2-or-41612500khz14yes
USB-AIO12-1616 SE, 8 DIF1244250kHzYesRefsLearn Morerefs1416-io-8-8yes16-se-8-dif2-or-41612250khz14yes
USB-AIO12-16E16 SE, 8 DIF1244100kHzYesNoLearn Moreno1416-io-8-8yes16-se-8-dif2-or-41612100khz14yes
USB-AI12-16A16 SE, 8 DIF1244500kHzYesYesLearn Moreyes1416-io-8-8yes16-se-8-dif6341612500khz14yes
USB-AI12-1616 SE, 8 DIF1244250kHzYesRefsLearn Morerefs1416-io-8-8yes16-se-8-dif6341612250khz14yes
USB-AI12-16E16 SE, 8 DIF1244100kHzYesNoLearn Moreno1416-io-8-8yes16-se-8-dif6341612100khz14yes
USBP-II8IDO4A2 SE1614kHzNoNoLearn Moreno641no5716298-in-4-outnoyes2-seyes634no4-ss164khz1yes

PCI

Model# of InputsRes BIP RGUni RGSpeedFIFOAutocalLearn Morehf:att:pa_addr-cfghf:att:pa_autocalhf:att:pa_baudhf:att:pa_bip-rghf:att:pa_bip-rg-inputhf:att:pa_buffhf:att:pa_bus-connhf:att:pa_cable-lengthhf:att:pa_cable-typehf:att:pa_connectorhf:att:pa_coshf:att:pa_counter-resolutionhf:att:pa_counter-typehf:att:pa_countershf:att:pa_digital-i-ohf:att:pa_fifohf:att:pa_four20mahf:att:pa_inputshf:att:pa_isolationhf:att:pa_kithf:att:pa_lrg-fifohf:att:pa_on-board-calhf:att:pa_optoshf:att:pa_outputshf:att:pa_pcie-laneshf:att:pa_pcie-x1-expansionhf:att:pa_proghf:att:pa_prot-cfghf:att:pa_quad-inputshf:att:pa_receiver-typehf:att:pa_relayhf:att:pa_reshf:att:pa_res-inputhf:att:pa_rs-232hf:att:pa_rs-422hf:att:pa_rs-485hf:att:pa_speedhf:att:pa_uni-rghf:att:pa_uni-rg-inputhf:att:pa_xt
LPCI-AIO16E16 SE, 8 DIF1664250kHzYesRefsLearn Morerefs636616-io-8-8yesno16-se-8-dif21216250khz24no
LPCI-AIO16A16 SE, 8 DIF1664500kHzYesRefsLearn Morerefs636616-io-8-8yesno16-se-8-dif21216500khz24no
PCI-A12-16A16 SE, 8 DIF1244100kHzYesLearn More4324-i-o-8-8-8yesyes16-se-8-dif12100khz4
PCI-AI12-1616 SE, 8 DIF1244100kHzNoLearn More432-i-onoyes16-se-8-dif12100khz4no
PCI-AI12-16A16 SE, 8 DIF1244100kHzYesLearn More432-i-oyesyes16-se-8-dif12100khz4no

PC/104

Model# of InputsRes BIP RGUni RGSpeedFIFOAutocalLearn Morehf:att:pa_addr-cfghf:att:pa_autocalhf:att:pa_baudhf:att:pa_bip-rghf:att:pa_bip-rg-inputhf:att:pa_buffhf:att:pa_bus-connhf:att:pa_cable-lengthhf:att:pa_cable-typehf:att:pa_connectorhf:att:pa_coshf:att:pa_counter-resolutionhf:att:pa_counter-typehf:att:pa_countershf:att:pa_digital-i-ohf:att:pa_fifohf:att:pa_four20mahf:att:pa_inputshf:att:pa_isolationhf:att:pa_kithf:att:pa_lrg-fifohf:att:pa_on-board-calhf:att:pa_optoshf:att:pa_outputshf:att:pa_pcie-laneshf:att:pa_pcie-x1-expansionhf:att:pa_proghf:att:pa_prot-cfghf:att:pa_quad-inputshf:att:pa_receiver-typehf:att:pa_relayhf:att:pa_reshf:att:pa_res-inputhf:att:pa_rs-232hf:att:pa_rs-422hf:att:pa_rs-485hf:att:pa_speedhf:att:pa_uni-rghf:att:pa_uni-rg-inputhf:att:pa_xt
104-AIM-32A32 SE, 16 DIF126100kHzNoNoLearn Moreno6noyes32-se-16-dif12100khz550yes
104-AIM-3232 SE, 16 DIF6NoNoLearn Moreno6noyes32-se-16-dif637638550yes
104-AI12-881222100kHzNoNoLearn Moreno2224-i-o-8-8-4-4noyes86341212100khz22yes
104-AIO12-881222100kHzNoNoLearn Moreno2224-i-o-8-8-4-4noyes841212100khz22yes
104-AIO16A16 SE, 8 DIF1662500kHzYesRefsLearn Morerefs636616-io-8-8yesno16-se-8-dif21216500khz22yes
104-AIO16E16 SE, 8 DIF1662250kHzYesRefsLearn Morerefs636616-io-8-8yesno16-se-8-dif21216250khz22yes

Remote Data Acquisition

ModelDescriptionLearn More
RAD242These cards are 24-bit parallel, digital input/output cards designed for use in PCI-Bus computers. The difference between the models is that I/O connections to PCI-DIO24D are via a standard 37-pin D-sub connector while I/O connections to PCI-DIO24H are via a 50-pin connector. The cards are 4.80 inches long (122 mm) and may be installed in any 5V PCI-bus slot in IBM and compatible personal computers.Learn More
RIDACSLearn More