Calibration and Maintenance
UMSITRPSD3-1
November
2010
7-8
7.3.2 Digital Output (Communication)
A malfunctioning digital output can indicate a defective communication circuit. More commonly,
however, these problems are caused by an incorrect or poor installation. It is possible to install a
transmitter such that the 4-20 mA signal is correct, yet the digital HART signal is not.
The most common symptom of a communication problem is the inability to locate a transmitter on the
loop using a HART Master Device, such as the HART Communicator. Typical messages from the HART
Communicator include: device disconnected, no device found, or communication error.
If communication problems occur, check the following. Refer to the specifications in Section 9 and to
Section 4 Installation as necessary.
•
Check that loop resistance is between 250
Ω
and 1100
Ω
.
•
Check that electrical noise on the loop is not excessive: power supply ripple should not exceed 12
mVp-p.
•
Check that there are no high inductance devices in the loop (I/P for example). Install a HART
communication filter across such a device.
•
Check that the power supply voltage is high enough for the installed total loop resistance. Refer to
Section 4 Installation.
•
Refer to Section 4 Installation and confirm that loop cable length is not excessive.
•
Check that the HART Master is connected across a load.
Summary of Contents for 7MF4033 series
Page 48: ...Model 275 Universal Hart Communicator UMSITRPDS3 1 November 2010 2 26 ...
Page 86: ...Installation UMSITRPDS3 1 November 2010 4 34 ...
Page 152: ...Calibration and Maintenance UMSITRPSD3 1 November 2010 7 20 ...
Page 158: ...Circuit Description UMSITRPDS3 1 November 2010 8 6 ...
Page 197: ......
Page 198: ......
Page 200: ...Model Designations and Specifications UMSITRPDS3 1 November 2010 9 42 ...
Page 204: ...Glossary UMSITRPDS3 1 November 2010 10 4 ...
Page 208: ...Appendix A Online Configuration Map UMSITRPDS3 1 11 4 November 2010 ...
Page 216: ...Appendix C Elevation and Suppression Correction UMSITRPDS3 1 13 4 November 2010 ...