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Model 10A79-4
Analog Peak Capture Card

This extremely useful four-channel card can be remotely controlled to provide

Real-time capture of analog-signal peak values, both positive and negative (up to four inputs)

The Model 10A79-4 will detect and store in analog (capacitor) memory the most positive and most negative values experienced by a given analog input signal since the input channel in question was last reset by an appropriate logic "TRACK" command.  Each peak value will remain in memory until reapplication of the respective "TRACK" command, or until occurrence of a subsequent more positive or more negative signal excursion (thus permitting the capture of successively higher maxima or successively lower minima).

The diagrams at the bottom of this page show the different possible modes of real-time peak capture (and reset); see Section 3.A.4 of the System 10 User's Guidebook for complete details.

Click here for an illustration of a system that uses specially modified Model 10A79-4 cards for life-cycle testing of pressure switches.

Since they are stored in on-board capacitor memory, captured peak values are subject to slow analog decay (see Specifications).  However, you can easily arrange for any and all positive or negative peaks reported by a 10A79-4 channel to be indefinitely (digitally) held, without decay, by entering a CALCULATE (CLC) command of the form CLC x = MAX CHN y or CLC x = MIN CHN y (see diagram at the bottom of this page).

Real-time "MAX minus MIN" measurement (up to four inputs)

The Model 10A79-4 can measure the real-time difference between the most positive and most negative values detected for a given analog input signal since the input channel was last reset (see the diagram at the bottom of this page).  This feature, which required that the input be set to "MAX-MIN" mode, is particularly useful when you need to know the precise range of an excursive phenomenon like the runout, wobble, or looseness of a rotating part.

If you wish to display a given "MAX-MIN" value for any length of time, without decay, you can apply a LOCK (LOK) command to the channel in question.

Real-time analog "TRACK and HOLD" operation (up to four inputs)

When set to this mode of operation, any of the 10A79-4's four input channels will—upon release of the "TRACK" condition—instantly freeze its present value in analog memory.  The value will remain frozen until reapplication of the "TRACK" command to that channel.

If you wish to display a given "held" value for any length of time, without decay, you can apply a LOCK (LOK) command to the channel in question

Real-time unscaled analog signal buffering (up to four inputs)

The 10A79-4 provides buffering of up to four analog signals for continuous, real-time, unscaled output to various external devices (for scalable buffering, see the Model 10AAO-4 Analog Buffer Card). 

Each of the 10A79-4's four analog inputs can be internally hard-wired to any selected Conditioner Card within the system that has "AUXILIARY OUTPUT" provisions (see Specifications, below)—or to any other internal source of the standard ± 5 VDC data signal.  Each 10A79-4 channel may be assigned the same "TYPE" code as its respective "source" conditioner channel, or it may be assigned a special "Conversion Channel" code of E8.  Use of this special type code greatly simplifies setup of the 10A79-4 channel, which is now automatically loaded with the calibration values currently in effect for the "source" channel.

As shown in the following diagram, each of the four inputs produces

	Two internal SYSTEM DATA CHANNELS: (1) "+ PEAK" and (2) either "MAX-MIN" or "-PEAK," depending on the input's mode setting.  These channels can be displayed on the system data display, if present, and can be interrogated like any other standard data channels via the CHANNEL (CHN) command.
	Two ANALOG OUTPUTS: (1) "+PEAK" and (2) "-PEAK."  Available at the 10A79-4's rear I/O Connector, these signals can be sent in turn to a strip-chart recorder or similar device, or can serve as fast "real-time" inputs to a PID servo controller.

One or both a given analog input's data channels (and corresponding analog outputs) can be easily converted to "TRACK and HOLD" operation, when the input is set to "-PEAK" mode.

As shown in the diagrams below, the 10A79-4's PEAK-CAPTURE, "MAX-MIN," and/or "TRACK AND HOLD" process is completely controlled by logic-level inputs received at the card's rear I/O Connector from a Universal Logic I/O Card (either a Model 10AIO-16 or Model 10BIO-16) or from an external logic source.  There are two such logic inputs for each analog input channel: "TRACK / NOT + PEAK" and "TRACK / NOT MAX-MIN."

Standard processing functions may be applied to any of the internal data channels generated by the 10A79-4, including calculations, dual limit monitoring, etc.

Model 10A79-4 Specifications  [Top ]
Inputs	Four standard "System 10" ± 5 VDC analog data signals from user-specified Conditioner Cards or other data-signal sources within the system, via direct hard-wire connection on the mainframe's Analog Motherboard*
Amplifier (per channel)
Input Impedance (Differential)	Greater than 1 MΩ
Offset	Initial: ±1 mV Vs. Temperature: ±0.25 mV/°C Vs. Time: ±1 mV/month
Gain Accuracy	±0.02% of full scale
Gain Stability	Vs. Temperature: ±50 ppm/°C Vs. Time: ±10 ppm/month
Analog Filtering
Filter	3-pole modified Butterworth; -3 dB at 200 Hz; -60 dB at 3.4 kHz
Step Response Settling Time (Full-Scale Output)	To 1% of final value: 5 ms To 0.1% of final value: 7 ms To 0.02% of final value: 10 ms
Analog Memory Decay Rate**	Does not exceed 1 mV/sec
Analog Outputs (per input channel)	"+ PEAK" and "-PEAK" available at rear connector; there is no direct "MAX-MIN" analog output.  The full-scale amplitude of any given output will be a function of the "Type" designation of the respective analog input channel.
* The following cards do not produce "Auxiliary Output" and may therefore not be directly connected to the Model 10A79-4 without special modification: 10A9-8C, 10A10-4, 10A15-8, 10A35, 10A62-8C, 10A64-8C, 10A65-8, and 10A69-4. ** This is small enough to allow essentially perfect capture of signal peaks using the "MAX/MIN" CALCULATE (CLC) commands.