Martel Electronics 320 User Manual

MODEL 320

PRESSURE CALIBRATOR

& LOOP

POWER SUPPLY

USER’S GUIDE

TABLE OF CONTENTS

INTRODUCTION Page

General Description………...…………………….4 Model 320 Calibrator…………………..…………4 Loop Power Supply (LPS)………………..………4 Battery Charging………………….………………5

Operation – Model 320 Calibrator

Power On Sequence…………………..…………..6 Battery Check - Model 320 Calibrator…...……….9 Battery Check - Loop Power Supply………...……9

Select Key..............................................................10

Zero Key................................................................10

Min/Max Key.........................................................11

Eng Units Key........................................................12

Damp Key..............................................................12

Port Select Key.......................................................13

mA/V Key..............................................................14

% Key.....................................................................14

Trip Reset Key........................................................15

Clear Key................................................................17

Setup Key and Menus.............................................17

User Eng..........................................................18

Batt. Save........................................................20

% Function......................................................21

H2O Ref..........................................................24

Owner..............................................................24

Calibration.......................................................26

Trip Detect.......................................................33

Input Functions

Volts........................................................................34

Milliamps................................................................34

Pressure...................................................................35

Differential Absolute Vacuum

Operation - Loop Power Supply

Power On/Off Sequence.........................................36

Battery Check.........................................................36

How To Use The LPS.............................................36

Application Notes

Using the Model 320 Calibrator With A

Hand Pump.…………………………………….....38

Using the LPS..........................................................41

Pressure Switch Calibration Using Trip

Detect.........……………………………………......43

Calibrating a Pneumatic Transmitter.......................44

Calibration Using % Function.................................45

Appendix

A. Entering Alphanumeric Data..............................47

B. Pressure Conversion Factors..............................48

Specifications

Pressure...................................................................50

mA/V.......................................................................51

Environmental.........................................................51

Service Information

Warranty.................................................................53

Return For Calibration/Repair................................54

INTRODUCTION:

GENERAL DESCRIPTON

The Model 320 pressure calibrator is a compact, versatile, functionally styled calibrator. The unit is menu driven, so technicians can immediately begin using it to its fullest capabilities without extensive training.

The Model 320 faceplate consists of three functional areas:

At the top is a two line, alphanumeric liquid crystal display (LCD) for simltaneous indication of pressure and milliamps/volts readings and operator prompting.

The center section is a membrane keypad for operator entry.

The lower left section contains recessed input jacks for connecting the supplied test leads to the device being calibrated.

The pressure connectors are at the lower end of the case and are 1/8” FNPT.

The Loop Power Supply (LPS) is an option that provides 24 VDC to power the device under test if

desired. The LPS is stored in a pouch under the Model 320 calibrator for easy access.

BATTERY CHARGING

Units are shipped with the internal batteries in an uncharged state. Before using the Model 320 or the

LPS as a portable unit, it is necessary to charge the batteries for a minimum of 14 to 16 hours. The

calibrator battery charger is a wall plug-in type (see below) that connects to a jack on the right-hand side of the instrument. Battery operation time is 50 hours, typically for the Model 320 and 6 hours nominal at 20 milliamps for the LPS.

OPERATION:

The Model 320 calibrator is user friendly and menu driven. A first time user can normally start operating the unit with few or no instructions. The following information is intended to provide a detailed understanding of the unit.

POWER ON SEQUENCE

The calibrator is turned on or off by pressing the On/Off key. Each time it is turned on, a series of internal tests and calibrations are performed. The start-up procedures provide a pass/fail test of certain internal circuitry. If the tests determine the unit has an internal failure, a fault message is displayed and the unit will not operate. Refer to the Service Information on page 54 for information on how to contact the factory.

The start-up calibrations provide for dynamic recalibration of the internal calibrator support circuitry, by applying the primary reference voltages to points in the circuitry and recording the readings as references for further measurements. The start-up

auto calibration does not in any way affect the primary calibration done at the factory or at a field metrology lab using available software and suitable standards.

During the time the start-up tests and calibrations are being performed, certain informational displays are presented to show the status of the calibrator. The first message displayed will be:

Beta Gauge

01/04/94

This indicates the date in MM/DD/YY format of the last factory calibration. The example indicates the Model 320 was calibrated on Jan. 4, 1994. If the unit has been recalibraed in the field, the date will be displayed in a MM-DD-YY format. See page 26 for a description of the calibration procedure.

The next display will be:

property of

YOUR NAME HERE

This gives the name of the owner of the calibrator. The preceding display shows the default setting as the calibrator is shipped. The name can be changed through the operator setups. See page 24 for how to change the owner’s name.

The next display will be:

Auto Calibration

in progress

This display will remain until the internal tests and calibrations are finished. If the auto calibration message fails to clear, the unit must be returned for service. See page 54 for details. The next display will be the functions that had been selected when the calibrator was last used:

inH2O mA

0.0 0.000

This display indicates the calibrator is operating properly and is ready to go to work.

BATTERY CHECK

The Bat Ck key may be pressed at any time after completion of the calibrator startup routine to diplay the current batttery voltage for approximately 1 second before the normal display returns. The current input funciton is not disturbed by making a battery check measurement.

The battery voltage of the Model 320 calibrator should be between 5.3 and 4.6 volts. When the voltage falls below 4.8 volts, a warning message is displayed approximately every minute. When the voltage falls below 4.6 volts for 1 minute, the calibrator will turn itself off to prevent damage to the batteries due to possible reversal.

The batteries of the LPS are checked by plugging the cable provided with the LPS into the battery charger jack located on the side of the LPS. The other end of the cable should be plugged into the Model 320 V input. When voltage is selected on the keypad, the LPS battery voltage will be displayed on the Model

320.

The LPS battery voltage should be between 10.6 and

9.2 volts, indicating a full charge. When the voltage falls below 8.8 volts, the LPS will turn itself off to prevent damage to the batteries due to possible cell reversal.

SELECT KEY

The Select Key is used for two functions. First, while in Setup, pressing Select will switch the dispay from two sets of menu screens. Second, Select is used in the field calibration described on page 26.

ZERO KEY

When the Model 320 is first turned on, a small zero offset may appear. Pressing the zero key wil eliminate it. A warm up of up to four minutes may be required to achieve nominal accuracy. For absolute pressure sensors only, the following procedure may be used. Press the Zero Key. The calibrator will request the user to enter the calibration access code (found on the factory calibration data sheet.) After entering the code and pressing the enter key, the calibrator will prompt the user to enter the new zero (actual barometric

pressure). A barometric standard of at least .025% accuracy should be used to determine atmospheric pressure. When entering this value, proper decimal place entry must be observed.

The “Zero” key is inactive during user calibration. Only numeric entry (9) is active in this mode.

MIN/MAX KEY

The Model 320 calibrator constantly monitors the displayed readings and stores the minimum and maximum values internally.

Pressing the Min/Max key will cause the minimum and maximum values to be displayed. The maximum values will be displayed on the top line and the minimum values will be displayed on the bottom line. Pressing the Min/Max key a second time will return the Model 320 to a normal display mode and will reset the minimum and maximum values to the current reading.

The minimum and maximum values are also reset whenever a new function or engineering unit is selected.

ENG UNIT KEY

The Eng Unit key allows the user to select any of the 8 standard or 1 user definable engineering units to be activated for the pressure display. Each time the Eng Unit key is pressed, the next engineering unit is selected. Engineering units which exceed PSI resolution, will not be valid. Example, 50,000 counts, when converted from the 5000.0 PSIG converted to mmHg equals 258,575 mmHg. This exceeds 50,000 counts and will not be an active unit of measurement.

If a user defined engineering unit has been entered, it is displayed as the 9th entry. The user defined entry can always be identified by a “u” in the first position, followed by the name.

The user defined engineering uits are configured from the operator setup functions (UsrEng).

DAMP KEY

The Damp key alternately enables or disables damping of the displayed pressure measurements. When damping is active, the Model 320 displays a running average of the last 16 measurements rather

than the instantaneous values. This feature is useful when measuring pressures that are pulsating or otherwise unstable.

The Model 320 makes 2-3 pressure measurements per second. When the Damp mode is active, the Model 320 updates the display each time a measurement is made. The displayed is the average of the last 16 measurements.

PORT SELECT KEY

The Port Select key is used to select either or both of the pressure ports to be displayed on dual sensor 320 calibrator models.

If the Model 320 is equipped with dual pressure sensors, pressing the Port Select key will alternately select the left port, the right port, or both ports.

If both ports are selected, the Model 320 will display both pressures simultaneously but milliamps or volts cannot be displayed.

If one port is selected, the Model 320 will display one pressure and either milliamps or volts.

MA/V KEY

The mA/V key will alternate the electrical measurement being displayed between milliamps and volts.

% KEY

Pressing the % key will cause the Model 320 calibrator to switch from displaying in the selected engineering units to displaying the readings as a percentage. The Model 320 percent function is a powerful feature that greatly simplifies the calibration of I/P, E/P, P/I, P/E AND P/P transmitters. When the percent function is active, the input to the instrument being calibrated is displayed as a percent of full scale, and the output from the instrument being calibrated is displayed as an error percent.

To utilize the percent function, the operator should first utilize the setup function (% func) to enter the desired zero and full scale values required for the calibrator. This is described on page 21.

Once the proper zero and full scale values have been entered, the operator presses the % key to activate the percent function. The zero and span adjustments to the transmitter can now be quickly adjusted by applying aproximately 0% and 100% inputs to the transmitter as shown on the display, and adjusting the output for 0% error as shown on the display.

After the zero and span adjustments have been made, the linearity can be quickly checked by applying various intermediate inputs and noting the error directly in percent. If there is no error, 0% will be displayed for any pressure input.

The application note on page 45 gives examples for using the percent function.

Pressing the % key a second time will return the display to the selected engineering units. The percent mode is also terminated if a new function or engineering unit is selected.

TRIP RESET KEY

The Trip Rst key is used in conjunction with the trip

detect mode that is available through the setup menus. When trip detect is active, the Model 320 calibrator will monitor the electrical measurement for a significant change of state. When a change of state is detected, the last pressure measurement is frozen on the display, and the message “tripped” is displayed over the electrical measurement.

When the Trip Rst key is pressed, the Model 320 will resume displaying the instantaneous pressure and monitoring for a change of state at the electrical terminals.

The message “ready” will be displayed over the electrical measurement.

A change of state is signified by a 10% change in either the volts or milliamps reading. When trip detect is active, voltage measurements will be made on the 30 V scale and milliamps measurements will be made on the 50 mA scale. The Model 320 makes 2-3 electrical measurements per second. To guarantee that the change of state will be detected, the change must exist for a minimum of ½ second.

For a hook-up diagram, refer to the application note on page 43.

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