Altek Model 311 Universal RTD Calibrator Manual

							GENERAL INFORMATION
ALTEK
UNIVERSAL RTD CALIBRATOR
MODEL 311
Simulate & Read RTDs
Altek’s Model 311 RTD Calibrator lets you
SIMULATE and READ RTD’s over the entire
industrial temperature range.  Use with transmitters,
recorders controllers, alarms, indicators, data
acquisition and computer systems.  Switch between
four platinum 100 ranges, one platinum 200 range,
one platinum 500 range and two platinum 1000
ranges.  The Model 311 also has ranges for copper
and Nickel and can be supplied with custom RTD
ranges.  When custom ranges are installed, one or
more of the standard ranges is deleted.  Call the
factory for details.
Calibrate RTD Instruments
Simulate RTD resistances into all types of
measuring instruments. The Altek Model 311 takes
the place of bulky, expensive decade boxes and
temperature tables. Output directly in °C, °F or dial in
the resistance value in ohms.  
QUIK-CHEK Outputs
Save time with every calibration by instantly
recalling three output settings with the handy QUIK-
CHEK switch. All output settings are remembered,
even with the power off.
Compatible With Modern Instruments 
The Model 311 has been designed to calibrate a wide
variety of RTD devices, supporting devices with excitation
currents of as little as 0.090 mA and as high as 10.20 mA. 
Some newer process control equipment use a pulsed
excitation current to measure RTD sensors. This includes
some smart transmitters, multi-channel recorders and
inputs to computers and digital control systems.
The Model 311 is designed to work with these devices
and accepts intermittent current pulses as short as 56
milliseconds.  
Read RTD Sensors
The Model 311 display gives you fast, accurate
temperature measurement with 0.1° and 1° or resistance
measurement with 0.01Ωand 0.1Ωresolution. Two, three
and four wire hookups assure accuracy in long cable
runs. Open RTDs and leads are detected and indicated
on the LCD display. Two readings per second track fast
moving temperatures. 
MAX and MIN memories are continuously updated
from turn-on or whenever the  RESET button is pressed.
Model 311 gives you a handy tool to monitor
temperatures for drift or control deviation. Just flip the
QUIK-CHEK switch to display the MlNimum and
MAXimum temperature measured since reset.
ALTEK INDUSTRIES CORP • CALIBRATE IN TEMPERATURE FOR YOUR RTD TYPE
Select Platinum 100, 200, 500 and 1000 Ohm
Copper 10 Ohm
Nickel 110 and 120 Ohm
• SIMULATE RTDS INTO PROCESS INSTRUMENTS
Operates with devices that use pulsed excitation currents
including Rosemount Smart Transmitters
• CALIBRATE WITH LABORATORY ACCURACY
±(0.01% of Reading + 0.075 Ohms)
Accurate to ±0.2 °C (0.4 °F) for Pt 100 Ohm RTDs
• RESOLUTION TO 0.1 °C OR °F
• DIGITAL ACCURACY WITH ANALOG SIMPLICITY
Speed sensitive digital pot for fast output adjustment
• USER SETTABLE “QUIK-CHEKS
©”
Set any Span & Zero for instant recall
• STANDARD  “AA” ALKALINE BATTERIES
50 hours of constant operation
• THREE YEAR WARRANTY
Toolbox tough
• CUSTOM RANGES AVAILABLE
Additional RTD types, base resistances or Alpha values 
						

							OPERATING INSTRUCTIONS
Connections
The Model 311 accurately simulates and reads 2,
3, or 4 wire RTDs. Press the 2, 3, 4 WIRE push-
button to match the instrument being calibrated.
All connecting wires must be the same length and
of the same material running along the same path
to insure maximum accuracy.
Two, Three or Four Wire
Two wire RTD measurements are less accurate
than other RTD measurements because of the
errors introduced by the resistance of the lead
wires. The third wire in a three wire hookup pro-
vides the instrumentation with a reference con-
nection for the lead wires. The measuring instru-
mentation uses this reference to infer the actual
resistance of the RTD element without the leads.
Four wire RTD measurements take into account 
all wires other than the RTD sensing element.
This makes four wire RTDs best suited for preci-
sion measurements.
Compatibility with Excitation Currents
RTD measuring instruments use different levels of
excitation current to read RTDs. The 311 operates
with excitation currents from 0.090 to 10.20 mA.
As the excitation current increases the highest
resistance that can be simulated decreases. With
currents from 0.090 to 1.2 mA the 311 can simu-
late up to 2000Ω. At 5.00 mA of excitation the
highest simulated resistance is 500Ωand at 10.20
mA the highest simulated resistance is 250Ω.
Some transmitters, recorders and other RTD input 
devices use intermittent, or pulsed, excitation cur-
rents to measure the resistance of the RTD. The
Model 311 may be configured to operate with both
fixed excitation currents (default operation) and
with intermittent currents as fast as 56 millisec-
onds (see User Options below).
Changing RTD Types
Eleven RTD types or ohms may be selected to
match the sensors and instruments in your plant.
The symbol Alpha (α) is used to identify the partic-
ular RTD curve. The value is derived by dividing
the resistance of the sensor at 100°C by the resis-
tance at 0°C (α= R100°C/R0°C). For Pt 100
DIN/IEC/JIS this is 138.50/100.00 = 1.3850. This
value is sometimes represented as 0.00385 or
simply as 385.
To change RTD types:
1) Turn the selector knob to the desired Metal (Pt,
Cu, Ni or to Ohms. Note that for  the most
common RTD type, Pt 100ΩDIN/IEC/JIS α=
1.3850, there is a dedicated position on the
selector.
2) For Pt and Ni sensors there are a choice of sev-
eral αvalues. Press the SETUP push-button to
scroll through the available α curves.
Note:The Pt 200Ω, 500Ω& 1000Ωcurves are
not available when Intermittent Current
Compatibility is enabled.
Changing Batteries
Low battery is indicated by BAT on the LCD dis-
play. Approximately 10 hours of operation remain
before the LCD goes blank and the Model 311
shuts itself down. Turn the Model 311 off, loosen
the screw on the battery compartment and lift off
the battery compartment door. Replace the six
“AA” batteries, replace the door and tighten the
screw.
Auto-Off
The 311 can be set up to turn itself off after 30 minutes of inactivity. The
internal timer is reset to 30 minutes each time the digital pot is turned or
a push-button is pressed. This configuration is part of the DEFAULT SET-
TINGS.
Enabling Intermittent Excitation Current Compatibility
The 311 may be configured to operate with instruments that use only con-
stant excitation currents or with a mix of instruments that use constant or
intermittent excitation currents. This configuration is part of the DEFAULT
SETTINGS.
Configuring Temperature Scales
The 311 may be configured for full time use of °C, full time use of °F or
selectable °C and °F operation. This configuration is part of the DEFAULT
SETTINGS.
Selecting Autoranging or 1° Resolution
The Model 311 may be configured to autorange or to constantly display
with fixed resolution. When autoranging is selected, the Model 311 will
display temperatures with 0.1° or 1° resolution. When fixed range is
selected, the Model 311 will display temperatures with 1° resolution.This
configuration is part of the DEFAULT SETTINGS.
Note:Some ranges are always displayed with 1° resolution.
General
User Options
DEFAULT SETTINGS - USER OPTIONS
The 311 may be restored to the factory settings. This will reset the HI,SET
and LO “QUIK-CHEK” memories for all RTD types to 0 °C (32 °F) and the
Ωrange to 100Ω. Prompts also guide you for selection of Auto-Off,
Intermittent Current Compatibility, temperature scale(s) and resolution.
1) Press and hold the STORE/RESET push-button while turning the 311 on.
2) Keep pressing the STORE/RESET push-button until the display
flashes (about 5 seconds) then release.The revision number of the
firmware will be displayed for a few seconds.
3) After five seconds the words SETUP, BAT and on will appear on the
display indicating that AUTO-OFF is selected.
4) To toggle the AUTO-OFF function on and off press the SETUP push-
button and the words on and OFF will display.
5) After five seconds the 311 will automatically store your choice and the
words SETUP, OFF and a symbol for pulsed current (a waveform) will
display indicating that Intermittent Current Compatibility is off.
6) To toggle Intermittent Current Compatibility on and off press the
SETUP push-button and the words on and OFF will display.
7) After five seconds the 311 will automatically store your choice and the
word SETUP, and the symbols °C & °F will display.
8) Press the SETUP push-button to make your selection. With °C
flashing the unit will only display in °C, With °F flashing the unit will
only display in °F and with both flashing you can select °C and °F for
each T/C & RTD type. °C/°F is selected if no push-buttons are
pressed.
9) After five seconds the 311 will automatically store your choice and the
word SETUP and 0.1° will appear on the display.
10) To toggle the resolution press the SETUP push-button to switch
between 0.1° and 1°.
11)After five seconds the 311 will automatically store your choice and the
311 will begin normal operation.
Pt
Cu
Ni
Ω
SETUP
WIRE 2, 3, 4 
						

							OPERATING INSTRUCTIONS
Read
1) Set up the Model 311 for the correct RTD type
and temperature scale (°C or °F).
2) Disconnect the wires from the resistance sen-
sor to be read or checked.
3) Connect the Model 311 to the sensor to be
measured, being careful to observe proper
connections for 2, 3 or 4-Wire hookups.
4) Display present reading, Maximum or
Minimum temperature.
Input
Whenever READ mode is selected the word
READ will appear on the LCD. The Model 311 can
measure temperatures with resolution of 0.1° and
1° and resistance in two ranges with resolution of
0.01Ωand 0.1Ω. The display is updated twice per
second to continuously track fast moving temper-
atures. Using three or 4-Wire hookups provides
accurate readings in long cable runs.
SOURCE
1) Set up the Model 311 for the correct RTD 
type and temperature scale (°C or °F). 
2) Disconnect the input wires from the device 
to be calibrated or checked.
3) Connect the Model 311 to the device to be 
calibrated, being careful to observe proper 
connections for 2, 3 or 4-Wire hookups.
4) Turn the digital pot to the desired output value. 
OUTPUT
Whenever SOURCE is selected the word
SOURCE will appear on the LCD. SOURCE will
flash when the Model 311 is measuring the exter-
nal excitation current and will be steady when
accurately simulating a resistance. To change the
output value, turn the speed sensitive digital pot.
Turning the pot slowly will cause a gradual change
in the output. A faster change will occur when the
pot is turned faster. This function operates in all
three output positions (HI, SET & LO). 
NOTE:  If SOURCE never stops flashing on the
LCD the excitation current is out of range, too
noisy or is intermittent.  Check to see that the
device being calibrated has operating power and
that the 311 is properly connected. Also check the
manual for the device to make sure that the exci-
tation current is in the range of 0.090 to 10.20 mil-
liamps.
Hint:Some “smart” transmitters and scanning
recorders or indicators use intermittent currents to
measure RTD’s. The Model 311 can be configured
to accept intermittent excitation with minimum 56
milliseconds fixed current (see Compatibility with
Intermittent Excitation Currents).
Source (Resistance Output or RTD Temperature Output)
STORE
1) Switch to HI (or LO).
2) Turn the digital pot to desired value.
3) Press STORE push button.
If a value is in the SET position and you want that
value in HI or LO, press and hold the STORE but-
ton while moving the switch to HI or LO. Then
release the STORE button. When there is no exci-
tation current or the current is less than 90mA, the
digits will flash on the LCD. “QUIK-CHEK” values
may still be stored with the digits flashing.
“QUIK-CHEK”
Any time you need a stored value just throw the
“QUIK-CHEK” switch. Any value in the RTD range
may be stored in HI & LO. The Model 311 remem-
bers the HI, LO and SET values for you with the
power on or off. The resolution of the stored value
will be based on the excitation from the receiver.
When a new RTD type is selected, the resistance of
the sensor at 0°C is stored in all “QUIK-CHEK” posi-
tions. When the ohms range is selected,100Ωwill
be the initial setting for all “QUIK-CHEK” positions.
SELECTING FIXED/INTERMITTENT CURRENT
Operation with fixed or intermittent currents may be
chosen immediately after the 311 is turned on.
If Intermittent Excitation Current Compatibility has
been selected as a user option, the symbol for inter-
mittent current (a waveform) and the word on or
OFF will appear on the display each time the 311 is
turned on. To toggle between on (Intermittent
Compatibility) and  OFF (fixed current) press the
SETUP push-button. If the selection you want is
already displayed wait 3 seconds and the 311 will
begin operating.
Hint:Choose intermittent excitation onlywhen device to be calibrated uses inter-
mittent currents. Most devices require that fixed current operation is selected.
Open RTDs
The Model 311 checks for open or high resistance
connections. Open or burned out RTDS are indi-
cated by - - - - - on the display.
If the temperature is out of range the symbols or
and ur will appear on the display.
MIN/MAX
To read the Maximum or Minimum temperature
since READ mode was entered, simply switch to
MAX or MIN. The value will appear on the LCD
along with the word MAX or MIN. The MAX/MIN
values are automatically updated and may be
viewed at any time without disturbing the other val-
ues. Pressing RESET will transfer the present tem-
perature into both MAX and MIN and will update 
them as the measured temperature changes.
READ (Measure RTD Sensors or Resistors)
Connections
The Model 311 can be hooked up to instruments or sensors with two,
three or four wire connections. Use the diagram on the connection panel
(shown on the right) and match the resistor symbol to the diagram on the
instrument, sensor or the manual for the instrument. For two wire con-
nections, place a red lead in socket 1 and a black lead in socket 2. For
three wire connections place a red lead in socket 1, and black leads in
sockets 2 and 3. For four wire connections place red leads in sockets 1
and 4 and black leads in sockets 2 and 3.
SOURCEHI
SET
LO
RESET STORE
SOURCEHI
SET
LO
READMIN READMAX
READ SOURCE
READ SOURCE
°C / °F
°C / °F
WIRE 2, 3, 4
WIRE 2, 3, 4
14
2
3 
						

							SPECIFICATIONS
(Unless otherwise indicated, specifications are in % of Span in ohms with 1 mA fixed excitation current @ 23°C  for 1 year )
General
General Accuracy: ±(0.01% of reading + 0.075 Ohms)
Temperature Drift:± 0.01% / °C
Operating Temperature Range:-5 to 140 °F (-20  to 60 °C)
Storage Temperature Range:-22 to 170 °F (-30 to 80 °C)
Relative Humidity: 10 to 90%, non-condensing
Warm Up Time:30 seconds to maximum accuracy
Battery Life:6  “AA” Alkaline Batteries:  Nominal 50 hours
Low Battery: “BAT” indication on LCD at 7 Volts nominal,
approximately 10 hours left.  Batteries should be removed
when storing the unit for longer than three months.
Overall Size: 6.23 x 3.27 x 1.94 inches (158.1 x 83.1x 49.3 mm)
Weight: 1lb, 2oz (0.5 kg)
New Product Information
This document contains information for a new product. Altek
Industries Corp reserves the right to modify this product
without notice.SOURCE MODE (SIMULATION OF RESISTANCE)
Output Resistance Ranges:
0.00 to 409.99 and 410.0 to 2010.0 Ohms
Accuracy from 1 to 10 mA of External Excitation Current:
±(0.01% of reading + 0.075 Ohms)
Accuracy Below 1 mA of External Excitation Current:
±(0.01% of reading +                              + 0.05 Ohms)
Allowable External Excitation Current:0.09 to 10.20mA
Intermittent Excitation Currents: Accepts intermittent
excitation currents with minimum of 56 milliseconds fixed
current at minimum repetition rate of 1/sec from 0.90 to 10 mA.
READ MODE (MEASUREMENT OF RTD SENSORS)
Input Resistance Ranges:
0.00 to 409.99 and 410.0 to 2010.0 Ohms
Accuracy: ±(0.01% of reading + 0.075 Ohms)
Excitation Current Supplied: 1 mA, nominal
Normal Model Rejection:  50/60 Hz, 50 db
Common Mode Rejection: 50/60 Hz, 100 db
ADDITIONAL INFORMATION
Three Year Warranty
Our equipment is guaranteed against defective material and workmanship
(excluding batteries) for a period of three years from date of shipment.
Claims under guarantee can be made by returning the equipment prepaid
to our factory. The equipment will be replaced, repaired or adjusted at our
option. The liability of Altek is restricted to that given under our guarantee.
No responsibility is accepted for damage, loss or other expense incurred
through sale or use of our equipment. Under no condition shall Altek be
held liable for any special, incidental or consequential damage.
Other Products
Altek designs and manufacturers fast, accurate instruments for
measurement, generation and simulation of virtually every process control
signal. Consult our factory directly or contact your local stocking
representative to order precise, low cost Milliamp Calibrators, Voltage
Sources, Thermocouple Sources, RTD Simulators, Frequency Calibrators
and Pressure Pumps, Indicators & Calibrators. Altek also produces
calibrators for custom ranges and unique applications. New models are
frequently added to the Altek family to meet all of your critical calibration
requirements. Altek products are made in the USA.0.025 mV
mA Excitation Current
RANGES AND ACCURACIES
(Temperature Accuracies Converted From Resistance  – Based On Ohms Accuracy of ±(0.01% of Reading + 0.075Ω)
RTD TYPE ALPHA RANGE ACCURACY RANGE               ACCURACY
Pt 100Ω(DIN/IEC/JIS 1989)     1.3850 -200.0 to 200.0°C ±0.2°C -328.0 to 392.0°F ±0.4°F
200.0 to 600.0°C ±0.3°C 392.0 to 1112.0°F ±0.6°F
600.0 to 850.0°C ±0.4°C 1112.0 to 1562.0°F ±0.7°F
Pt 100 (Burns) 1.3902 -195.6 to 200.0°C ±0.2°C -320.0 to 392.0°F ± 0.4°F
200.0 to 648.8°C ±0.3°C 392.0 to 1200.0°F ±0.6°F
Pt 100 (Old JIS 1981) 1.3916 -200.0 to 200.0°C ±0.2°C -328.0 to 392.0°F ±0.4°F
200.0 to 648.8°C ±0.3°C 392.0 to 1200.0°F ±0.6°F
Pt 100 (US Lab)                      1.3926 -200.0 to 100.0°C ±0.2°C -328.0 to 212.0° ±0.4°F
100.0 to 700.0°C ±0.3°C 212.0 to 1292.0°F ±0.6°F
700.0 to 862.2°C ±0.4°C 1262.0 to 1584.0°F ±0.7°F
Pt 200Ω(DIN/IEC/JIS 1989)     1.3850 -200.0 to 200.0°C ±0.1°C -320.0 to 392.0°F ±0.2°F
200.0 to 700.0°C ±0.2°C 392.0 to 1292.0°F ±0.4°F
700.0 to 850.0°C ±0.3°C 1292.0 to 1562.0°F ±0.5°F
Pt 500Ω(DIN/IEC/JIS 1989)     1.3850 -200.0 to 600.0°C ±0.1°C -320.0 to 1112.0°F ±0.2°F
600.0 to 850.0°C ±0.2°C 1112.0 to 1562.0°F ±0.3°F 
Pt 1000Ω(Hy-Cal/HVAC)         1.3750 -184 to 275°C ±1°C -300 to 527°F ±1°F
Pt 1000Ω(DIN/HVAC) 1.3850 -200 to 265°C ±1°C -328 to 510°F ±1°F
Cu 10 (Minco)                         1.4274 -200 to 260°C ±2°C -328 to 500°F ±4°F
Ni 120 (Pure) 1.6720 -80.0 to 315.5°C ±0.1°C -112.0 to 524.0°F ±0.2°F
Ni 110 (Bristol 7 NA) 1.5801 -106.7 to 315.6°C ±0.2°C -160.0 to 600.0°F ±0.3°F
Ohms 0.00 to 409.99Ω±(0.01% of Reading + 0.075Ω)
410.0 to 2000.0Ω±(0.01% of Reading + 0.075Ω)
Available From