Altek 311 Manual page 3

SOURCE
1) Set up the Model 311 for the correct RTD
type and temperature scale (°C or °F).
SOURCE
READ
2) Disconnect the input wires from the device
to be calibrated or checked.
3) Connect the Model 311 to the device to be
°C / °F
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-
2, 3, 4
nal excitation current and will be steady when
WIRE
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.
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).
Read
1) Set up the Model 311 for the correct RTD type
and temperature scale (°C or °F).
SOURCE
READ
2) Disconnect the wires from the resistance sen-
sor to be read or checked.
°C / °F
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
Minimum temperature.
Input
Whenever READ mode is selected the word
READ will appear on the LCD. The Model 311 can
2, 3, 4
WIRE
measure temperatures with resolution of 0.1° and
1° and resistance in two ranges with resolution of
0.01Ω and 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.
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.
OPERATING INSTRUCTIONS
Source (Resistance Output or RTD Temperature Output)
Check to see that the
READ (Measure RTD Sensors or Resistors)
present reading, Maximum
STORE
HI
SET
LO
SOURCE
STORE
RESET
"QUIK-CHEK"
HI
SET
LO
SOURCE
SELECTING FIXED/INTERMITTENT CURRENT
Hint: Choose intermittent excitation only when device to be calibrated uses inter-
mittent currents. Most devices require that fixed current operation is selected.
Open RTDs
or
MIN/MAX
MAX
READ
MIN
READ
Connections
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.
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,100Ω will
be the initial setting for all "QUIK-CHEK" positions.
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.
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.
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.
1 4
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