Application Faults Without Messages; Spare Parts - Endress+Hauser iTEMP TMT184 PROFIBUS-PA Manuel De Mise En Service

9 Troubleshooting
Application fault without
messages

Spare parts

76
9.3

Application faults without messages

General process faults
Fault
No communication
Faulty connection to control system
There is no connection between the control system and the measurement unit.
Check the following points
Fieldbus voltage (only on PROFIBUS-
®
PA )
Network structure
Basic current
Termination resistance
Current consumption
Allowable loop current
Fault
Incorrect/inaccurate measured value
9.4 Spare parts
Head transmitter installation set (4 screws, 6 springs, 10 circlips)
Order No.: 51003264
When ordering accessories or spare parts, please state the serial number of the head transmitter!
Cause
No power supply on the 2-wire con-
nection
Power supply too low (<10 V)
Interface cable defective
Interface defective
Head transmitter defective
Check if a minimum bus voltage of 9 V DC is available on terminals 1/2. Allo-
wable range 9 to 32 V DC
Check allowable fieldbus length and number of spurs, see page 52
Is there a basis current of 10 ± 1 mA available?
Is the PROFIBUS network correctly terminated? Basically both ends (beginning
and end) of each bus segment must be terminated with a bus termination resis-
tance. Otherwise interference could occur on communication.
Check the current consumption of the bus segment:
The current consumption of the bus segment concerned (= sum of basic cur-
rent of all bus users) must not exceed the max. allowable loop current of the
bus power unit.
Cause
Sensor incorrectly positioned
Heat conducted via sensor
Transmitter set-up incorrect (number
of wires)
Incorrect RTD or thermocouple set up
Connection of sensor (RTD, 2-wire)
Sensor cable resistance (RTD, 2-wire)
not compensated
Incorrect cold junction set-up (TC con-
nection)
Offset set-up incorrectly
Faults via the thermowell welded
thermo cable on TC connection
(adding interference voltage)
TMT184
Action/cure
Connect the cables correctly accor-
ding to the terminal layout (polarity)
Check power supply
Check interface cable
Check PC interface
Replace head transmitter
Action/cure
Install sensor correctly
Note position of the sensor
Change parameter "Connection
mode"
Change parameter "Sensor type"
Check connection of sensor
Compensate for cable resistance
→ chap. 10.0.2
Check offset
Use a sensor on which the thermo
wire is not welded
Endress+Hauser