Martel Electronics PTC8010 - Manual (Page 16)

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Note: The calibrator simulates a 2-wire RTD. To connect 3- or 4-wire transmitter, use stacking
cables, as shown in Figure 15.
4.4-1 Custom RTD
A custom curve-fit PRT may be entered into the calibrator for sourcing and measuring. To
do so follow these steps:
1. Select the [CONFIG] option from the main menu. Select RTD and set sensor type
to CUSTOM.
2. Enter the RTD custom setup main menu, and select [SET CUSTOM].
3. Using the keypad, enter the values that the calibrator prompts for: minimum
temperature, maximum temperature, R0, and the values for each of the
temperature coefficients.
The custom function uses the Calendar-Van Dusen equation for outputting and measuring
custom RTDs. The coefficient C is only used for temperatures below 0°C. Only A and B
coefficients are needed for the range above 0°C, so coefficient C should be set to 0. The
R0 is the resistance of the probe at 0°C. The coefficients for PT385, PT3926, and PT3616
are shown in Table 4 below.
Table 4. RTD Coefficients
RTD Range(°C) R0 Coefficient A Coefficient B Coefficient C
PT385 -260 - 0 100 3.9083x10-3 -5.775x10-7 -4.183x10-12
PT385 0 - 630 100 3.9083x10-3 -5.775x10-7 ---
PT3926 Below 0 100 3.9848x10-3 -5.87x10-7 -4x10-12
PT3926 Above 0 100 3.9848x10-3 -5.87x10-7 ---
PT3916 Below 0 100 3.9692x10-3 -5.8495x10-7 -4.2325x10-12
PT3916 Above 0 100 3.9692x10-3 -5.8495x10-7 ---
5. Remote Operation
The calibrator can be remotely controlled using a PC terminal, or by a computer program
running the calibrator in an automated system. It uses an RS-232 serial port connection for
remote operation. With this connection the user can write programs on the PC, with Windows
languages like Visual Basic to operate the calibrator, or use a Windows terminal, such as
Hyper Terminal, to enter single commands. Typical RS-232 remote configurations are shown
in Figure 16.