AM1640 Precision Industrial PRT User’s Guide
Rev. 201609V3
5/10
3 General Operations
3.1 Connecting to the readout device
The AM1640 is equipped with a four-wire cable (see Figure 1). Four
lead wires are used to cancel lead wire resistance. For best results, the
readout device should be equipped to handle four-terminal resistors.
The lead wires can be distinguished by insulation colors. Lead wire
pairs attached to each end of the sensor are identified by red/black and
white/blue insulation.
3.2 Drive Current
AccuMac recommends 1mA as drive current to ensure the best
measurement.
3.3 Stability of Readings
To achieve the best accuracy, allow sufficient time for PRT to
stabilize before taking the readings.
3.4 Immersion Requirements
Stem effect can cause measurement errors due to heat lost or gained
by the sensing element through the thermometer stem. To minimize
the error, appropriate immersion depths are required. A practical way
to determine the minimum immersion depths is to change the depth
Figure1
Black
Blue
White
Red
