Ashcroft ATE-100 Handheld LCD Digital Calibrator User Manual

Page 35

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Revision 4.6 3/2004

Probe: 12345678

P&a385 RO = 100

Step 13

With the desired probe type selected and flash-

ing press the enter key.

ENT

The calibrator will respond by displaying the following:

Resolution:

1 .1 .01 0.001

The maximum resolution that the combination of the
Calibrator base unit, RTD interface module and probe
can support can be determined as follows:

The resolution of the RTD module is 0.001% of the
full scale resistance of the reference resistor used in the
module. The GQS-RT1 incorporates a 400 ohm refer-
ence resistor and the GQS-RT2 incorporates a 4000 ohm
reference resistor.

Using the GQS-RT1 as the example the maximum reso-
lution is:

0.001% of 400 ohms

= 0.00001 x 400 = 0.004 ohms

For a PT 100 the temperature resolution can be deter-
mined as follows:

0.004 ohms/(100 ohms x 0.00385 ohms/degree C) =
0.008 degrees C (approx 0.005 degrees F)

Therefore, rounding to the next highest digit results in a
resolution of 0.01 degrees C.

The resolution supported for the factory programmed
RTDs can be found below:

Using the RT-1

Probe Type Resolution
Pt 100

0.01 degrees C or F

(385 & 392)

ni 120

0.1 degrees C or F

Cu 10

0.1 degrees C or F

Using the RT-2

Probe Type

Resolution

Pt 1000

1.0 degrees C or F

Resolution must be selected in conjunction with the full
scale ohms output for the RTD probe to be used.

Step 14

Select the desired resolution using the left/right

arrow keys. In this case, since we are using the Pt100
RTD with a maximum resolution of 0.01 degrees C the
0.01 option has been selected

Resolution:

1 .1 01 0.001

Step 15

With the desired resolution selected and flash-

ing press the enter key.

ENT

The calibrator will briefly show internal limit settings
and will then commence temperature measurement.

The measurement parameters can be changed at any
time through the activation of the RTmodule set up menu.

Section 16.2

Calibrating/Programming the

GQS-RT RTD Interface Module

The GQS-RT can be programmed in the field. Program-
ming, calibration adjustment or recertification can be
accomplished with the Calibration Programming Utility
disk. Please note, in order to improve the accuracy of
the measurement system it will be necessary to gener-
ate a significant number of very accurate temperature
calibration points using precision temperature baths. In
general, the simplest way to enhance the accuracy of the
temperature measurement is to simply re-zero the probe
while immersed in an ice bath.

Section 17.0 Thermocouple Interface Module

The Thermocouple Interface Module allows the hand-
held calibrator base unit (equipped with firmware version
3.01 or later) to read the input from a thermocouple
temperature measuring device. The calibrator offers the
following features for thermocouple measurement:

• Selectable units of measure

• Direct millivolt readout for any type of thermocouple

• Choice of internal or external refernce junction

• Selectable resolution, or “auto” mode

• Programming to allow readout in temperature units for
the following 8 thermocouple types:

Type Materials
J

Iron & Copper-nickel (Constantan)

nickel-Chromium & nickel-Aluminum

Copper & Copper-nickel (Constantan)

nickel-Chromium & Copper-nickel

(Constantan)

Platinum-13% Rhodium & Platinum

Platinum-10% Rhodium & Platinum

Platinum-30% Rhodium & Platinum

– 6% Rhodium

nickel-Chromium-Silicon & nickel-Silicon-

Magnesium