Altek Model 934 Milliamp Voltage Loop Calibrator Manual

							16
OPERATING INSTRUCTIONS
SOURCE MODE
STORING QUIK-CHEK OUTPUTS
1) Switch to HI or LO
2) Turn the knob to desired value
3) Press the 
STORE push-button
The LCD will flash once to show that
the value was saved
If a value is in the SET position and you
want that value stored in HI or LO, press
and hold the 
STORE push-button while
moving the switch to HI or LO. The display
will flash once to indicate the value has
been stored. Then release the 
STOREpush-button.
RECALLING QUIK-CHEK OUTPUTS
Any time you need a stored value just
flip the QUIK-CHEK  switch. Any value for
the selected range may be stored in HI &
LO. The Model 934 remembers the HI,
LO and SET values for all ranges
(32 memories)  with the power on or off.
Each time a different range is selected,
the last three QUIK-CHEK  values for that
type will be recalled.
+
HI
SET
LO
STORE


29
OPERATING INSTRUCTIONS
READ MODE
MIN/MAX
To read the Maximum or Minimum
INPUT 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 values.
RESTARTING MIN/MAX
Pressing the 
RESET push-button will
cause the 934 to store the present read-
ing into the MIN and MAX memories.
Upon releasing the 
RESET push-button
the Model 934 will resume reading the
input and update the MAX & MIN values
as the measured signal changes.
OUT OF RANGE SIGNALS
Signals above or below those available
for the currently selected range will be
indicated by OVER and UNDER on the
display.
+MAX
MIN READ
OVER
UNDER 
						

							15
OPERATING INSTRUCTIONS
SOURCE MODE
Whenever SOURCE mode is selected the word SOURCE
will appear on the LCD display. To change the output value,
turn the speed sensitive digital pot. Turning the knob slowly
will cause a gradual change in the output. A faster rate of
change will occur when the knob is turned faster. This function
operates in all three output positions (HI, SET & LO).
ALTEK 934
20.000mA
VA LV E
OR
RECEIVER I/P
30
OPERATING INSTRUCTIONS
READ FUNCTIONS
The READ functions measures the desired signal.
Multiple scales are available for each function. Engineering
Units & % DP Flow must be enabled before they are
available for selection.
READ MILLIAMP OUTPUTS
mA, mA %, mA ENG. UNIT, mA % DP FLOW
Choose this function to measure from -52.00 to +52.00
milliamps. For calibrating controller output and checking process
loop currents the input is autoranged to higher resolution from
-24.000 to +24.000 milliamps.
1) Open the current loop at any convenient point along the
signal path
2) Connect the red 
READ (+) lead of the calibrator to the
more positive point of the break and the black READlead (-) to the more negative
Display the present reading, Maximum or Minimum by moving
the toggle switch from READ to MAX or MIN. If the Model 934
is connected in the wrong polarity, the display will indicate
negative current. Simply reverse the leads for correct indication.
COMPUTER
CONTROLLER
RECEIVER
POWER
SUPPLYSENSOR OUTPUT
ALTEK 934
12.000mA 
						

							14
OPERATING INSTRUCTIONS
SOURCE MODE
SOURCE
1) Move the POWER switch to ON
2) Press & hold both the STORE & RESET push-buttons for 1
second to enter the SETUP mode. The word SETUP will
appear in the LCD and the words SOURCE and READ will
alternately flash. Release both push-buttons.
3) Press the 
STORE push-button. The words SETUP and
SOURCE will remain on the LCD and the previously selected
function will repeatedly flash.
4) Turn the knob (Digital-Pot) to scroll through the available
functions. Each enabled function will flash on the LCD (See
ENABLING RANGES & FUNCTIONS, page 6).
5) Press the 
STORE push-button to select the function.
If AUTO-CHEK has been enabled you can choose to
have the 934 automatically step the output (See AUTO-
CHEK, page 24). If AUTO CHEK is not enabled or selected
the 934 will immediately output the prior value for that
function. If OFF is selected the SOURCE function will be
deactivated and the top half of the LCD will be blank.
6) Adjust the knob to the desired output value or QUIK-CHEK
with previously stored outputs (see STORING QUIK-CHEK
OUTPUTS, page 16).
7) Connect the Model 934 to the input terminals of the instrument
or meter to be calibrated.
31
OPERATING INSTRUCTIONS
READ VOLTAGE OUTPUTS
V, mV, V ENG. UNIT
Choose this function to measure from -99.990  to + 99.990
Volts. For checking sensor outputs and other low level signals
the input is autoranged to display from -999.90 to +999.90
millivolts.
1)
Connect the red READ (+) lead and the black READ lead(-) of the calibrator across the voltage to be measured.
Loop power supplies, signal voltages at receivers, batteries,
transmitter voltage drops and any other voltages may be
measured. Signals above or below those available for the
currently selected range will be indicated by OVER and
UNDER on the display.
ANALYZER
VOLTAGE
SOURCE
mV SOURCE
ALTEK 934
24.000V 
						

							13
OPERATING INSTRUCTIONS
USING ENGINEERING UNITS
8) The word SPAN and ENG.
UNIT will appear in the
bottom half of the LCD
prompting you to enter the
highest value for the range
in the units to match the
display of the instrument
being calibrated. Turn the
knob until the highest value
of your chosen range
flashes in the bottom half of
the LCD. Press the 
STOREor RESET push-button to
continue.
9) The Model 934 will now
begin operating with the
ranges and Engineering
Units you have selected. If
Engineering Units have
been chosen for any
Source function the HI &
LO QUIK-CHEKs will
automatically be updated
with the units you have
chosen. Refer to the
sections for READ or
SOURCE FUNCTIONS for
further instructions.
S
E
T
U
P
SPAN ENG. UNIT      ZERO
ENG. UNIT
ENG. UNITSOURCE
ENG. UNITSOURCE
   0.00
mA  mA
500.00   0.00
   500.00
HI
LO
32
SPECIFICATIONS
(Unless otherwise indicated, specifications are in ±% of Reading @ 23°C)GENERAL
ACCURACY: ±(0.012% of Reading + 0.008% of Full Scale Reading)
WARM UP TIME: 10 seconds to specified accuracy, 2 minutes
to maximum accuracy
TEMPERATURE EFFECT: ±0.008%/°C based on 23°C±25°C
ISOLATION: 500 VDC between SOURCE & READ leads
BATTERIES: Six “AA”, (R6) batteries (Alkaline supplied
and recommended)
BATTERY LIFE:
MILLIAMP SOURCE & 2-WIRE MODES: Nominal 33
hours at 12 mA, 20 hours at 20 mA into 250 Ohm load
OTHER FUNCTIONS: Nominal 40 hours
AC ADAPTORS: Optional, nominal115 or 230 VAC, 50/60 Hz
LOW BATTERY INDICATION: “BAT” indication on the display
at approximately 4 hours left
OVERVOLTAGE PROTECTION: Protected to 120 Volts AC or
DC in all ranges without fuses for 30 seconds
OUTPUT NOISE: ≤ 1 LSD at frequencies less than 10 Hz
NORMAL MODE REJECTION RATIO: 50 dB @ 50/60Hz
COMMON MODE REJECTION RATIO: Not applicable for
battery operation. 120 dB @ 50/60 Hz with AC Adaptor
OPERATING TEMPERATURE RANGE:
-5 to +130°F (-20 to +55°C)
STORAGE TEMPERATURE RANGE:
-13 to +130°F (-25 to +55°C)
RELATIVE HUMIDITY: 10 to 90%, non-condensing for 24
hours from 0 to 35°C
OVERALL SIZE: 
6 11/16 x 4 x 2 15/16 inches (170 x 102 x 75 mm)
WEIGHT: 1lb, 9oz (0.709 kg)
Accuracy of scaled ranges (% of 4 to 20 mA, %DP Flow, Engineering
units) are based on the value of the fundamental units (mA , V or mV).
Accuracies of the Source and Read ranges are independent. When
Source and Read are connected together the accuracies are additive. 
						

							12
OPERATING INSTRUCTIONS
USING ENGINEERING UNITS
6) You are now prompted by
flashing zeros to enter the
decimal point position for the
engineering units you have
chosen. Turn the knob until
the decimal point appears in
the location to match the
resolution of the display on
the instrument you will be
calibrating (from zero to
three digits to the right of the
decimal point). Press the
STORE or RESET push-
button to continue.
7) The word ZERO and ENG.
UNIT will appear in the top
half of the LCD prompting
you to enter the lowest value
for the range in the units to
match the display of the
instrument being calibrated.
Turn the knob until the
lowest value of your chosen
range flashes in the top half
of the LCD. Press the
STORE or RESET push-
button to continue.
S
E
T
U
PENG. UNIT
S
E
T
U
P
SPAN ENG. UNIT      ZERO
ENG. UNIT
   0.00
   0.00   0.00
33
SPECIFICATIONS
MILLIAMP SOURCE
RANGES:
0.000 to 24.000 mA
-25.00 to 125.00% of 4 to 20 mA
-50.0 to 111.8% of % DP Flow
Scaled Engineering Units (from -90000 to +90000
counts with up to three digits to the right of the decimal
point)
ACCURACY: ±(0.012% of Reading + 0.008% of 24.000 mA)
TYPICAL DRIVE CAPABILITY: 1200 Ohms @ 20.000 mA
POWER TO DRIVE RECEIVER: nominal 24 VDC
COMPLIANCE VOLTAGE:
0 to 285 Ohm load: 10V nominal
285 to 1200 Ohm load: 24V nominal
OVERLOAD PROTECTION: Current limited to 25 mA
POWER & MEASURE 2-WIRE
TRANSMITTERS
RANGES & ACCURACY: Same as for MILLIAMP
SOURCE above
OUTPUT CURRENT: up to 24.000 mA
TYPICAL DRIVE CAPABILITY: 1200 Ohms @ 20 mA
POWER TO EXTERNAL 2-WIRE TRANSMITTER:
nominal 24 VDC
OVERLOAD PROTECTION: Current limited to 25 mA 
						

							11
OPERATING INSTRUCTIONS
USING ENGINEERING UNITS
3) Turn the knob (Digital pot)
to scroll through the
available functions. Each
enabled function will flash
on the LCD.“ ENG. UNIT”
will appear as a choice for
each SOURCE or READ
function. Press the 
STOREor RESET push-button to
proceed.
4) The word ZERO will appear
in the top half of the LCD
prompting you to enter the
lowest value for the range in
mA, V or mV that will be
sourced or read. Turn the
knob until the lowest value
of your chosen range
flashes in the top half of the
LCD. Press the 
STOREor RESET push-button to
continue.
5) The word SPAN will appear
in the bottom half of the LCD
prompting you to enter the
highest value for the range
in mA, V or mV that will be
sourced or read. Turn the
knob until the highest value
of your chosen range
flashes in the bottom half of
the LCD. Press the 
STOREor RESET push-button to
continue.
S
E
T
U
PSOURCE
mA
ENG. UNIT
mA ZEROS
E
T
U
P
mA    SPAN
4.000
0.000
mA ZEROS
E
T
U
P
mA    SPAN
4.000
20.000
34
SPECIFICATIONS
2-WIRE TRANSMITTER SIMULATOR
RANGES:
3.000 to 24.000 mA
-6.25 to 125.00% of 4 to 20 mA
-25.0 to 111.8% of % DP Flow
Scaled Engineering Units (from -90000 to +90000
counts with up to three digits to the right of the decimal
point)
ACCURACY: ±(0.012% of Reading + 0.008% of 24.000 mA)
LOOP VOLTAGE LIMITS:
Minimum, 3 VDC; Maximum 45 VDC
OVERLOAD PROTECTION: Current limited to 25 mA
MILLIAMP READ
RANGES:
-52.00 to -24.001
-24.000 to +24.000 mA2
24.00 to 52.00 mA1
-25.00 to 125.00% of 4 to 20 mA
-50.0 to 111.8% of % DP Flow
Scaled Engineering Units (from -90000 to +90000
counts with up to three digits to the right of the decimal
point)
1ACCURACY: ±(0.012% of Reading + 0.008% of 52.00
mA)
2ACCURACY: ±(0.012% of Reading + 0.008% of 24.000 mA)
INPUT IMPEDANCE: 25 Ohms
VOLTAGE BURDEN:
0.2 V at 4 mA, 0.6 V at 20 mA, 1.4 V at 50 mA
MEASURING ACROSS A DIODE: Add ±0.2% to specification
from 0 to 20 mA (Diode 1N 914 or equivalent) 
						

							10
OPERATING INSTRUCTIONS
USING ENGINEERING UNITS
Scale the display of the Model 934 to match the display
of the instrument being checked. Any span in mA, mV or V in
Source or Read can be scaled to display between a
maximum of -90000 to +90000 with zero to three digits to
the right of the decimal.
The previously stored Engineering units can be recalled
by using the following procedure without turning the knob.
1) Press & hold both theSTORE & RESET push-
buttons for 1 second to enter
the SETUP mode. The word
SETUP will appear in the LCD
and the words SOURCE and
READ will alternately flash
(shown as gray). Release both
push-buttons.
2) Press the 
STORE push-
button to select SOURCE or
the RESET push-button to
select READ. The words
SETUP and SOURCE or
READ will remain on the LCD
and the previously selected
function will flash.
READ
S
E
T
U
PSOURCE
S
E
T
U
PSOURCE
mA
Diagrams show setting mA
Source for 4 to 20mA scaled
to 0.00 to 500.00 liters/hour.
The display can be scaled to calibrate a reverse acting
controller (4 mA = 100.0 and 20 mA = 0.0) or to check
an indicator reading negative numbers (0 mA = -500.00
and 20 mA = +500.00).
Hint: Source in Engineering units and fundamental
units at the same time. Setup Source for one unit and
Read for the other unit. Connect the Source and the
Read wires together (in series for mA, in parallel
for mV and V).
35
SPECIFICATIONS
VOLTAGE SOURCE
RANGES:
0.00 to 999.90 mVDC1
0.000 to 20.000 VDC2
Scaled Engineering Units (from -90000 to +90000 counts
with up to three digits to the right of the decimal point)
1ACCURACY: ±(0.012% of Reading + 0.008% of 999.90 mV)2ACCURACY: ±(0.012% of Reading + 0.008% of 20.000 V)
SOURCE CURRENT: > 24 mA
SINK CURRENT:  >16 mA from 1 to 5 VDC
OUTPUT IMPEDANCE: < 0.2 Ohm
LOAD RESISTANCE: > 3 Ohms
SHORT CIRCUIT DURATION: Infinite
OVERLOAD PROTECTION: Current limited to 50 mA nominal
VOLTAGE READ
RANGES:
-99.990 to -0.999 VDC1
-999.90 to 999.90 mVDC2
0.999 to 99.990 VDC1
Scaled Engineering Units (from -90000 to +90000 counts
with up to three digits to the right of the decimal point)
1ACCURACY: ±(0.012% of Reading + 0.008% of 99.900 V)2ACCURACY: ±(0.012% of Reading + 0.008% of 999.90 mV)
INPUT RESISTANCE: 2 Meg Ohm nominal
SOURCE RESISTANCE EFFECT: 0.01% error per 200 Ohms
MAXIMUM VOLTAGE LIMIT: 120 Volts DC to 100 Hz AC 
						

							9
OPERATING INSTRUCTIONS
 RANGES
MILLIVOLTS - mV
Choose mV to display directly in millivolts DC. Use 0 to 100
millivolts to check recorder or analyzer inputs. SOURCE from
0.00 to 999.90 mVDC. In READ the 934 autoranges between
-999.90 to +999.90 millivolts and -99.990 to +99.990 VDC.
ENGINEERING UNITS - ENG. UNIT
Choose ENG. UNIT to match the display of the instrument
being calibrated (see page 10 for instructions). Any span in
mA, mV or V in Source or Read can be scaled to display a
maximum of between -90000 to +90000 with 0 to three digits to
the right of the decimal point.
CHANGING BATTERIES
Low battery is indicated by BAT on the
LCD Display. Approximately 4 Hours
of operation remain before the LCD
goes blank and the Model 934 shuts
itself down.  Turn the 934 off, loosen
the three captive screws securing the
battery compartment cover. The six
“AA” batteries are easily removed and
replaced (alkaline supplied and
recommended). Replace the battery
compartment cover, tighten the screws
and turn on when ready to use.
36
MODEL 934 RANGES AND ACCURACIES
SPECIFICATIONS
Source mA & Simulate 2-Wire Transmitter1
    mA    LOW  HIGH    ACROSS2  LOW2  HIGH2OUTPUT    LIMIT  LIMIT    100 OHM   LIMIT   LIMIT
  24.000mA 23.995 24.005 (2.4000V 2.3995 2.4005)
20.000 19.996 20.004 (2.0000 1.9996 2.0004)
12.000 11.997 12.003 (1.2000 1.1997 1.2003)
4.000 3.998 4.002 (0.4000 0.3998 0.4002)
0.000 -0.002 0.002 (0.0000 -0.0002 0.0002)
Source % 4-20 mA & Simulate 2-Wire Transmitter1
%4-20mA   LOW  HIGH    ACROSS2  LOW2  HIGH2
OUTPUT    LIMIT  LIMIT    100 OHM   LIMIT   LIMIT125.00%   23.995 24.005 (2.4000V 2.3995 2.4005)
100.00 19.996 20.004 (2.0000 1.9996 2.0004)
50.00 11.997 12.003 (1.2000 1.1997 1.2003)
0.00 3.998 4.002 (0.4000 0.3998 0.4002)
-25.00 -0.002 0.002 (0.0000 -0.0002 0.0002)
Source % DP Flow & Simulate 2-Wire Transmitter
%FLOW    LOW  HIGH    ACROSS2  LOW2  HIGH2
OUTPUT    LIMIT  LIMIT    100 OHM   LIMIT   LIMIT100.00%DP 19.996 20.004 (2.0000V 1.9996 2.0004)
50.00 7.997 8.003 (0.8000 0.7997 0.8003)
0.00 3.998 4.002 (0.4000 0.3998 0.4002)
Power & Measure 2- Wire Transmitters
     mA    LOW  HIGH    ACROSS2  LOW2 HIGH2
OUTPUT    LIMIT  LIMIT    100 OHM   LIMIT  LIMIT
 24.000mA  23.995 24.005 (2.4000V 2.3995 2.4005)
20.000 19.996 20.004 (2.0000 1.9996 2.0004)
12.000 11.997 12.003 (1.2000 1.1997 1.2003)
4.000 3.998 4.002 (0.4000 0.3998 0.4002)
0.000 -0.002 0.002 (0.0000 -0.0002 0.0002) 
						

							8
√
OPERATING INSTRUCTIONS
 RANGES
The selected range is displayed on the LCD by the
annunciators listed below.
MILLIAMPS - mA
Choose mA to display directly in milliamps. Display in SOURCE
and READ functions from 0.000 to 24.000 mA. In READ you
can also measure up to 52.00 mA.
PERCENT OF 4 - 20 MILLIAMPS - mA %
Choose mA % to display in percent of span for 4 - 20 mA loops.
Use with chart recorders or current trips that display in %.
0.00% 4.000 mA
25.00%8.000 mA
50.00%12.000 mA
75.00%16.000 mA
100.00%  20.000 mA
Percent =  (mA-4)/0.16 mA =  (Percent/6.25) + 4
PERCENT DIFFERENTIAL PRESSURE - % DP
Choose % DP to display in percent of the square law for 4 - 20
mA loops. Also use to calibrate square root extractors and other
square law mA inputs.
0.0%4.000 mA
25.0% 5.000 mA
50.0% 8.000 mA
75.0% 13.000 mA
100.0%20.000 mA
%DP = (   mA-4) x 25 mA = (%DP/25)2+ 4
VOLTAGE - V
Choose V to display directly in DC Volts. Use for  0 to 1 Volt, 1
to 5 Volt or 0 to 10 Volt signals. SOURCE from 0.000 to 20.000
VDC. In READ the 934 autoranges between -999.90 to +999.90
millivolts and -99.990 to +99.990 VDC.
37
Source Volts
   VOLT   LOW  HIGH
  OUTPUT  LIMIT  LIMIT20.000V 19.997 20.003
10.000 9.998 10.002
5.000 4.998 5.002
1.000 0.999 1.001
0.000 -0.001 0.001
Source Millivolts
   mV   LOW  HIGH
OUTPUT  LIMIT  LIMIT999.90mV 999.701000.10
500.00 499.86 500.14
100.00 99.91 100.09
10.00 9.92 10.08
0.00 -0.08 0.08
Read mA3
     mA   LOW  HIGH
  INPUT   LIMIT  LIMIT
52.00mA 51.99 52.01
30.00 29.99 30.01
24.000 23.995 24.005
20.000 19.996 20.004
12.000 11.997 12.003
4.000 3.998 4.002
0.000 -0.002 0.002
Read Volts3
   VOLT   LOW  HIGH
  INPUT   LIMIT  LIMIT
99.990V 99.970 100.010
50.000 49.986 50.014
20.000 19.997 20.003
10.000 9.998 10.002
5.000 4.998 5.002
1.000 0.999 1.001
SPECIFICATIONS
MODEL 934 RANGES AND ACCURACIES
Read % 4-20 mA
    mA       %4-20mA LOW     HIGH
INPUT  INPUT LIMIT   LIMIT
24.000mA 125.00% 124.97 125.03
20.000 100.00 99.97 100.03
12.000 50.00 49.98 50.02
4.000 0.00 -0.02 0.02
0.000 -25.00 -25.01 -24.99
Read % DP Flow
  mA         %FLOW LOW    HIGH
INPUT       INPUT LIMIT     LIMIT
20.000mA   100.0%DP 100.0 100.0
8.000 50.0  50.0 50.0
4.000 0.0  -1.2 1.2
3LOW & HIGH LIMITS are identical
for negative readings
1Simulate 2-Wire Transmitter range
is from 3.000 to 24.000 mA
2100 Ohm resistor is used in the
calibration procedure (Seepage 38)
Read Millivolts3
  mV   LOW  HIGH
INPUT   LIMIT  LIMIT
999.90mV 999.70   1000.10
500.00 499.86 500.14
100.00 99.91 100.09
10.00 9.92 10.08
0.00 -0.08 0.08 
						

							BOTTOM BOARD
Calibrator Enabled
(Jumper Shorted)
on
off
CAL
7
OPERATING INSTRUCTIONS
ENABLING ADDITIONAL RANGES & FUNCTIONS
The DIP switches are located in
the battery compartment. Turn the
Model 934 off and loosen the three
slotted screws and remove the battery
cover.
38
CALIBRATION PROCEDURE
SUGGESTED EQUIPMENT
1) Digital voltmeter with accuracy of ±0.003% of reading at
2V and ±0.005% of reading at 100V
Important: The required accuracy is usually found
only on meters with 71/2  or more digits
2) 100 Ohm laboratory standard resistor with accuracy of
±0.003%
3) Adjustable DC Voltage source, 0 to 95.000 VDC with
resolution of 0.001 V and 0.01 mV
4) Adjustable DC current source, 0 to 24.000 mA with
resolution of 0.001 mA.
An 81/2Digit Multimeter with DC current accuracy of ±30 PPM
may be substituted for items 1 & 2 to calibrate the mA ranges
ENABLING CALIBRATION
Allow one hour for the Model 934 to
stabilize to the ambient temperature
of the calibration room. Remove the
battery cover and the 4 black phillips
head screws. While holding the 934
face down in one hand carefully
seperate the top and bottom of the
housing. Place the unit into calibration
mode by placing the jumper located
on the bottom board into the CAL
position.
During calibration the top half of the 934’s LCD display prompts
you with the input or output value being calibrated. The bottom half
indicates the measurement computed by the Model 934. When a
pushbutton is pressed to store a calibration reading the value in the
top half of the LCD flashes once. Please pause for 10 seconds before
proceeding for the 934 to compute the new calibration values.
Recommended calibration adjustments in this procedure have
been calculated  to 1/2of specification. See pages 36 & 37 for a table
of published specifications which may be used to obtain “As Received”
& “Adjusted” Test Data points.
*Factory default settings
4422AUTO-CHEK
Disabled AUTO-CHEK
Enabled*Engineering
Units Disabled* Engineering
Units EnabledENGINEERING UNITS
Switches between enabling and
disabling Engineering Units range
option for all functions AUTO-CHEK
Switches between enabling and
disabling AUTO-CHEK option for
source functionsAUTO-OFF
Switches between continuous
operation and automatic turn off
after 30 minutes of inactivityPERCENT DP FLOW
Switches between enabling and
disabling Percent DP Flow range
option for the milliamp functions
AUTO-OFF
Enabled*
Continuous
OperationPercent DP
Flow Enabled*
33
Percent DP
Flow Disabled
1(Switch
Up)1
(Switch
Down)