Changing Signal Parameters - Emerson Magtech LTM−350 Series Instruction And Operation Manual

August 2020
LCD did not initialize
properly
Local display
showing dark
black squares or
blinking "please
Electronics module
standby"
failure
Cannot enter into
menus local
Write protect jumper
display menus
is locking buttons
using push
buttons
If the mA output
greater than
22mA then
Electronics module
failure (most likely
Transmitter output
due to power surge)
does not match
If the mA output less
display
than 22mA
but slightly different
from
display then DAC
Trim

6.3 Changing Signal Parameters

There are 3 parameters involved with "Energy Settings".
These parameters are Energy, DCOffset and HoldTime.
•
Energy [%] is the amount of energy (a voltage
correlated to percentage) being sent down the
sensor probe.
•
DCOffet [V] is the DC voltage that the signal is
offset by. It is useful for eliminating some noise.
•
HoldTime [µs] is how long the Energy is sent down
for.
Symptom: Transmitter is erratic (i.e. output going
from correct reading to failure mode).
Cycle power rapidly
(this may have to
be done a few
times).
Replace electronics
with known
working electronics
from a sensor of
similar length
and/or contact
factory for
replacement
assistance.
Move the blue
jumper from the
right
(2pins) to the left
(2pins).
Consult factory for
replacement
assistance
(non-warranty)
Perform DAC trim
described in section
7.1.
19
Reference Manual
L231040 Rev AD
Possible Resolution:
Increase Energy Settings:
1. Unlock the pushbuttons by moving the blue jumper
to the left, Hold the UP button for 1sec
2. While holding the UP button also hold ENTER
button (together) for 3 secs
3. The menu should change to "ComPort" release the
buttons
4. Bypass this menu by pressing enter.
5. Keep bypassing the menus until you see "ChgSgnl",
6. Use the up or down arrows to change the "no" to a
"yes" and press enter.
7. The next Menu will say "Energy" and a
percentage, increase this number by 10 [%] and
press enter. (i.e. 20 to 30 %)
8. The next Menu will say "DCOffset", and a voltage,
leave this value unchanged and press Enter.
9. The next menu will say "HoldTime" and a number;
increase this number by 2 [µs] and press enter.
(i.e. 4 to 6 µs)
10. Then simply press enter until you see the "Exit"
menu and then press enter one last time.
The above procedure can also help if the output is in
constant failure mode.
please contact factory for further assistance. 1-800-221-
3653.
Section 7: LTM-350 has HART Protocol
7.0 Hart Protocol: General Information
The LTM-350 is a HART registered and certified instrument.
The section presents how the HART Communication
Protocol has been utilized in the LTM-350. This section
does not explain what HART Protocol is, please visit
www.hartcomm2.org to learn about HART.
If the procedure does not help