Hart Tm Resistor Selection - Ecom Instruments MCAL 4200 Instruction Manual

Figure 10. Connections for Sourcing Current
4.3-1 HART Resistor Selection
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The MCAL 4200 can be set-up so that the 250 ohm resistor required for Hart configuration
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devices resides inside the MCAL 4200. Enabling the MCAL 4200's internal 250 ohm resistor
eliminates the need to manually add a series resistor during a Hart calibration process.
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NOTE: When the MCAL 4200's internal 250 resistor is enabled, maximum load driving
capability drops from 1000 ohms @ 20mA to 750 ohms @20mA.
Enable/Disable Procedure
1. Remove the battery cover and remove the 2 screws that are at the top of the case.
2. Remove the 2 screws on the bottom or lower portion of the case.
3. Gently remove the top half of the case from the bottom.
4. Figure 10a. shows the location of the Hart jumpers.
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Figure 10a.
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