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Page 16                                                                         PRC70-EN-V2.1   12/11 

7.5.1 Temperature (TC) Monitor Function 

The calibrator offers a temperature monitor function convenient for observing the voltage value sourced between the output 
terminals in TC source mode. In the TC source mode, press the 

(START) 

key and the LCD will show the voltage value 

sourced between the output terminals (this value varies in response to the changes of the reference junction compensation). 
Press the

 (START) 

key again and the LCD will show the preset temperature value. 

 

7.6 Sourcing RTD Temperature 

z

  First, the calibrator sources a resistance signal by receiving the resistance-measuring current (I) supplied from the 

device being calibrated (such as a resistance meter) and then delivering the voltage (V) proportional to the preset 
resistance (R) between the output terminals, and thus producing the equivalent resistance R =V/I. Consequently, the 
calibrator sources the signal correctly only for such devices that employ this method of measurement. 

z

  The allowable range of the resistance measuring current that the calibrator receives from a resistance measuring device 

under calibration is rated as 0.1 to 3 mA. To ensure accuracy, the resistance measuring current from the device under 
calibration is strictly confined within this range. For further details, see the “Specifications” section. 

z

  Sourced resistance signals do not include the resistance component of the lead cables. The entire resistance, when 

measured at the ends of the lead cables for sourcing, is given by adding the resistance of the lead cables 
(approximately 0.1 ohms) to the sourced resistance signal. For the sourcing of precise resistance signals, use three-wire 
or four-wire connections. 

 
Step 1: 

Using the function key

 (FUNC)

, select the RTD function. Using the

 (RANGE) 

key, select a RTD range (PT100, 

PT200, PT500, PT1000, Cu10, Cu50). The selected function, the default range source value, and the unit of measure are 
shown in the lower area of the LCD. 

 
Step 2: 

Set the output value digit by digit using each pair of

S

/

T

keys.  

Each press of the

S

/

T

key increases or decreases the digit. Increasing the digit from 9 or decreasing it from 0 

causes the digit to overflow or underflow, allowing the output value to be set without interruption. Holding down the

S

/

T

key changes the digit in question quickly. And the value won’t change if it is increased or decreased to the Maximum or 

Minimum value. Pressing the

 (ZERO) 

key initializes the output set point to the default value (0). 

 
Step 3: 

Pressing the

 (ON) 

key causes the SOURCE indicator on the LCD to change from ‘’OFF‘’ to ‘’ON ‘’. The calibrator 

sources the preset resistance value between the output terminals. 

 
Step 4: 

To switch OFF the output, press 

(ON) 

again. The ‘’OFF‘’ icon appears on the LCD and no signals are sourced 

between the terminals. The connection methods based on three-wire and four-wire are shown in Figure 9. 

 
Note: 

The RTD source function is unavailable if the TC /RTD measurement function is ON.

 

 
7.6.1 Temperature Monitor Function 

The calibrator offers a temperature monitor function for easily observing the resistance value sourced between the output 
terminals. In the RTD source mode, press the

 (START) 

key and the LCD will show the resistance value sourced between the 

output terminals. Press 

(START) 

again and the LCD will show the preset temperature value. 

  

Summary of Contents for PRC70

Page 1: ...User Guide Multifunction Process Calibrator Model PRC70 ...

Page 2: ...In addition to the functions listed in Table 1 the calibrator includes the following features z Measure and source simultaneously The upper LCD area displays measurement information and the lower section displays source information z Thermocouple measurement source terminals and built in lead connector with RJ compensation z Manual step source auto step and sweeping step source z Room temperature ...

Page 3: ...limited warranty applies to sensors and cables If it should become necessary to return the instrument for service during or beyond the warranty period contact the Customer Service Department at 781 890 7440 ext 210 for authorization or visit our website www extech com for contact information A Return Authorization RA number must be issued before any product is returned to Extech The sender is resp...

Page 4: ...e for the measurement z Make sure the battery door is closed and latched before operating the meter z Remove test leads from the meter before opening the battery door z Inspect the test leads for damaged insulation or exposed metal Check test lead continuity Replace damaged test leads before using the meter z When using the probes keep fingers behind the finger guards on the probes z Connect the c...

Page 5: ...se Figure 2 Measurement Source Terminals Table 3 Measurement Source Terminals Terminal Function 1 Common COM return terminal for all measurement functions 2 Measurement Signals DCV OHM FREQ TC RTD SWITCH and CONT continuity 3 Measurement Signal mADC 4 3W Terminal measurement terminal of the 3W OHM RTD LOOP Terminal 24VDC Loop Power Terminal 5 Source Signal DCmA 6 Source Signals OHM RTD 7 Common CO...

Page 6: ...nt mode switch the RJ compensation ON OFF 18 ZERO Key Set the source value to zero point In pulse source function set the pulse number 19 Measurement RANGE Key Select measurement range Measurement mA and percentage shifting 20 Source RANGE Key Select source range Source mA and percentage shifting 21 AVG Key Measuring average value 22 25 100 key In mA source function select 25 or 100 manual step ou...

Page 7: ...red value k Unit of measure l Dividing line between measurement and source mode displays m Type of RTD measurement source n Dividing line between measurement and source mode displays o Type of Thermocouple TC measurement source p Reference Junction Compensation ON q 24V Loop Power Supply ON r Source Mode icon s Source function ON t Source function OFF u Set point for source v RUN icon for auto ste...

Page 8: ... cord plug from the wall outlet if using an AC Charger Use a soft damp cloth to gently wipe the outer surfaces of the instrument Water that is allowed into the instrument can result in malfunction z If using an AC Charger disconnect the power cord plug from the wall outlet when the meter is not in use z For handling precautions regarding the batteries see Installing or Replacing the Batteries z Ne...

Page 9: ... when the calibrator is in actual operation Consequently the indicator may read differently depending on the battery load condition e g the load condition of the source output or on off state of the measurement function Replace the batteries and fuses as described in the section Replacing or installing batteries and fuses toward the end of this User Guide Connecting the Charger Warning z Make sure...

Page 10: ...asured value to switch off and the OFF indicator to appear z To resume measurement when the MEASURE function is off press the MEASURE ON key again Automatic Power OFF When the calibrator is running on battery power and no key is pressed for approximately ten minutes the calibrator switches OFF automatically The automatic power off time can be programmed or set to the factory default state see the ...

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Page 13: ...p 80 seconds are required to finish a 4 20mA cycle in auto sweeping mode and 20 seconds are required for auto stepping mode Step 1 In the DC current mode press the key to display the auto stepping mode icon on the lower part of the screen press again to display the auto sweeping mode icon The default source value will display Step 2 Pressing the ON key causes the indicator on the LCD to change fro...

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Page 16: ... approximately 0 1 ohms to the sourced resistance signal For the sourcing of precise resistance signals use three wire or four wire connections Step 1 Using the function key FUNC select the RTD function Using the RANGE key select a RTD range PT100 PT200 PT500 PT1000 Cu10 Cu50 The selected function the default range source value and the unit of measure are shown in the lower area of the LCD Step 2 ...

Page 17: ...digit to overflow or underflow allowing the output value to be set without interruption Holding down the S T key changes the digit quickly The value won t change if it is increased or decreased to the Maximum or Minimum value Step 6 To re enter the frequency set mode and set the frequency press the FREQ key Step 7 Pressing the ON key causes the SOURCE indicator on the LCD to change from OFF to ON ...

Page 18: ...the S T key changes the digit quickly The value won t change if it is increased or decreased to the Maximum or Minimum value Step 8 To re enter the frequency set mode press the FREQ key Step 9 Pressing the ON key causes the SOURCE indicator on the LCD to change from OFF to ON and the calibrator sources low level signals between its output terminals Step 10 Press the START key to allow the calibrat...

Page 19: ... quickly The value won t change if it is increased or decreased to the Maximum or Minimum value Step 4 Pressing the ON key causes the SOURCE indicator on the LCD to change from OFF to ON Step 5 To switch the output OFF press the ON key again The OFF icon appears on the LCD and signals sourced between its terminals will be switched OFF Notes z The contact output source function is unavailable if th...

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Page 22: ... when carrying out the measurement tasks 8 2 Measuring DC Voltage Step 1 Ensure that the test lead cables are not connected to the instrument or device under test Step 2 Using the function key FUNC select the DC Voltage measurement function Step 3 Connect the test lead cables to the terminals of the instrument under test Step 4 Using the RANGE key select a range from 50mV 500mV 5V 50V The selected...

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Page 24: ...asured value and the unit of measure are displayed Notes z The RTD measurement function is unavailable if the TC RTD source function is ON z The calibrator defaults to the 3 wire connection method when measuring RTD When using the 2 wire connection method pay special attention to linking shorting the COM and LOOP terminals 7 6 1 Temperature Monitor Function The calibrator offers a temperature moni...

Page 25: ...upper part of LCD Pressing the HOLD key activates the HOLD mode and the LCD displays the HOLD symbol To exit HOLD mode press the HOLD key again the HOLD symbol switches OFF 9 Environmental Temperature Test The calibrator can measure the surrounding environmental temperature and display it on the top right corner of the LCD After switching the calibrator ON press the TEMP key to display the tempera...

Page 26: ...play the TEP U parameter at the top of the LCD if it s not already displayed Step 2 Shift between degrees C and F using the right pair of S T keys Step 3 To save the setting press and hold the SOURCE ON key until the LCD shows the SAVE symbol 10 4 Setting frequency Step 1 Use the MEASURE ON key to display the FrSEt parameter at the top of the LCD if it s not already displayed Step 2 Shift between ...

Page 27: ... expose batteries to fire z When replacing the batteries use only the specified type z Remove the batteries if the meter is to be stored for a long period Step 1 Remove the test leads and charger before replacing the batteries or fuses and switch OFF the meter Figure 16 Replacing batteries and fuses Step 2 Remove the protector as shown in Figure 16 With a standard blade screwdriver turn each batte...

Page 28: ...r Warning To avoid electrical shock or damage to the meter service the meter with specified replacement parts only and do not allow water to enter the meter housing Caution To avoid damaging the plastic lens and case do not use solvents or abrasive cleansers Clean the Calibrator with a soft cloth dampened with water or water and mild soap 13 2 Calibration Repair and Technical Support Services Exte...

Page 29: ...in Sensitivity 3Vp p min Duty Cycle 50 R 32 F to 3212 F 0 C to 1767 C S 32 F to 3212 F 0 C to 1767 C 1 8 F 1 C 32 F to 932 F 3 2 F 932 F to 3212 F 2 7 F 0 to 500 C 1 8 C 500 to 1767 C 1 5 C K 148 F to 2501 6 F 100 0 C to 1372 0 C 148 0 F to 32 0 F 2 2 F 32 0 F to 2501 0 F 1 4 F 100 0 C to 0 0 C 1 2 C 0 0 C to 1372 0 C 0 8 C E 58 0 F to 1832 0 F 50 0 C to 1000 0 C 58 0 F to 32 0 F 1 6 F 32 0 F to 1...

Page 30: ... 212 0 F 0 7 F 212 0 F to 572 0 F 0 9 F 572 0 F to 1166 0 F 1 3 F 200 0 C to 100 0 C 0 4 C 100 0 C to 300 0 C 0 5 C 300 0 C to 630 0 C 0 7 C Cu10 148 0 F to 500 0 F 100 0 C to 260 0 C 3 2 F 1 8 C RTD Cu50 58 0 F to 302 0 F 50 0 C to 150 0 C 0 1 F 0 1 C 1 3 F 0 7 C Pt100 385 curve standard Does not include lead resistance SWITCH CLOSE OPEN Approximately 1mA Test Current Short circuit display CLOSE ...

Page 31: ...he range of the internal temperature compensation sensor is from 10Ԩ to 50Ԩ compensation error 0 5Ԩ z Maximum voltage between VΩHz terminal and COM terminal 60 Vp p Maximum Input current 60mA Protected with a 63mA 250V fast blow fuse ...

Page 32: ...t 0 01mA Does not include lead resistance R 32 F to 3212 F 0 C to 1767 C S 32 F to 3213 F 0 C to 1767 C 1 F 1 C 32 F to 212 F 2 7 F 212 F to 3212 F 2 2 F 0 C to 100 C 1 5 C 100 C to 1767 C 1 2 C K 328 F to 2501 6 F 200 0 C to 1372 0 C 328 0 F to 148 0 F 1 1 F 148 0 F to 752 0 F 0 9 F 752 0 F to 2192 0 F 1 3 F 2192 0 F to 2501 0 F 1 6 F 200 0 C to 100 0 C 0 6 C 100 0 C to 400 0 C 0 5 C 400 0 C to 1...

Page 33: ... 3mA for Pt100 Cu10 Cu50 Excitation current 0 05mA 0 3mA for PT200 PT500 PT1000 Does not include lead resistance 100Hz 1 00Hz 110 00Hz 0 01 Hz 1KHz 0 100KHz 1 100KHz 1Hz 10KHz 1 0KHz 11 0KHz 0 1KHz 2 counts FREQ 100KHz 1KHz 110KHz 2KHz 5 counts 100Hz 1KHz PULSE 10KHz 1 100000 cyc 1 cyc 2 counts Output voltage 1 11 Vp p zero based waveform Amplitude accuracy 5 0 5V Maximum load 100 KΩ Duty Cycle 50...

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