Endress+Hauser Liquiline M CM42 - Page 17

CM42-MAA101EBE00 Diagnostics, troubleshooting
Endress+Hauser 17
3.1.4 Comunication-related errors
Current output, current
value incorrect
Incorrect adjustment Check with current simulation switched on,
connect mA meter directly to current output
.
Load too large
Shunt / short to ground in current
loop
No current output signal CPU defective Check with current simulation switched on,
connect mA meter directly to current output
.
Problem Possible cause Tests and/or remedial measures
No communication
possible
HART is connected to the wrong
current output
Connect HART to current output 1.
The device reboots Wait for the device to reboot. HART is available as
soon as the measuring screen is displayed.
Current output defective Check the output current at output 1 with an
external multimeter. If it is not possible to set a
current in the range between 3.6 and 21.5 mA, you
must replace the module.
No communication
possible or
communication is
unstable
Communication load (resistance)
outside the permitted range
Connect HART as shown in the wiring diagrams.
Preferably use a 250  resistor.
The device has been connected to an
input of a process control system
that is not designed for this purpose
(e.g. four-wire instead of two-wire).
Connect HART as shown in the wiring diagrams. An
external current source must be provided in the
circuit.
USB HART modem Alternatively use an RS232 modem. Some programs
have problems with USB modems. This has nothing
to do with CM42. Use hardware that you know will
work.
The control system cannot
switch on the burst mode
CM42 does not support the burst
mode
Use the device without the burst mode.
The unit of the
transmitted device
variable does not match
the unit on the display
The display and HART are
independent of one another
• Set the unit of the HART device variables with
FieldCare, for instance.
• Not all units are available through HART. In such
situations, the PCS displays "not defined" or , for
example, instead of M.
• Use a DD (device description) for your PCS. You
can download DDs and DTMs (Device Type
Managers) for common PCSs (FieldCare,
Pactware, ABB, AMS, PDM, FC475) from the
Endress website.
Problem Possible cause Tests and/or remedial measures