14
General Operational Guidelines
- All versions
1) Operation duty cycle
- Although the SMU has passed tests
that have accumulated over 150,000 operations, it is recom-
mended that the SMU be utilized as a periodic measurement
device. Applications requiring measurement more than fifty
times in a 24 hour period are not recommended. However,
there are no physical limitations to the number of operations
which can occur in one hour (i.e. the motor can run continu-
ously and not overheat). For a fully continuous measurement
device, consult the factory for other technologies.
2) Measurement rate
- The average measurement rate of an
SMU is influenced by the amount of cable on the storage reel.
The speed of the plumb bob descent and ascent is faster
when more cable is wound on the storage reel. The rate of
plumb travel can range from 1.0 ft/second to 1.5 ft/second
(300-450 mm/second).
3) Application restrictions
- The SMU is equipped with a motor
and spring tension system which is designed to maximize the
pull-out capacity in the event that a plumb bob becomes
entangled or buried. The SMU has been successfully tested
for operation in silo filling cycles in free flowing material appli-
cations. In applications where severe bridging or clinging
occurs, it is not recommended to operate during a filling oper-
ation. Consult the factory for additional recommendations.
Operation of SMU/HMI
2
System
1) Ensure SMU network address is set and that the HMI
2
chan-
nel is active.
2) Press MEAS to enter the measurement mode.
3) Use number pad to enter channel number, or use arrow key
to select "all" channel read.
4) Press ENTER.
5) If SMU is in “LOCKOUT” status, the SMU will not operate and
a message denoting such will be indicated on the HMI
2
display.
6) If SMU is not in “LOCKOUT” status, the SMU's plumb bob will
descend as depicted by "
i
" on HMI
2
display.
7) Upon material contact the new measurement will be dis-
played and the plumb bob will ascend as depicted by the "
h
"
on the HMI
2
display.
8) Once returned to the start/socket position, the "
h
" will disap-
pear. If any errors were detected, they will be indicated on the
HMI
2
. The following error conditions are analyzed and dis-
played if applicable.
Com Error: Communication between HMI
2
and SMU is
faulty
Return Error: The measurement of descent was greater
than the ascent
(If > 4” (100mm)+1% upward travel)
Index Error: The measurement of ascent was greater than
the descent (If > 4” (100mm))
Motion Error: The plumb bob did not move upon initiation of
a measurement cycle. (If < 4” (100mm))
OPERATION
Operation of SMU Analog(4-20mA) Output
1) Ensure the SMU is setup to correlate the 4mA and 20mA val-
ues to subsequent vessel values.
2) Initiate an SMU measurement with a contact closure on the
applicable sound input.
3) SMU's plumb bob will descend and the measurement process
will begin.
4) Upon material contact the new measurement will be output as
a 4-20mA signal and the plumb bob will ascend. The SMU
calculates between a range of 3-21.5 mA.
5) Once returned to the start/socket position, the following error
conditions are analyzed then indicated by the selected fail-
safe limit if applicable. If an error is detected, the 4-20mA
output will respond per the configured parameter
named “Err Sig”.
Return Error: The measurement of descent was greater
than the ascent (If > 4” (100mm)
+ 1% upward travel)
Index Error: The measurement of ascent was greater than
the descent (If > 4” (100mm))
Motion Error: The plumb bob did not move upon initiation of
a measurement cycle. (If < 4” (100mm))
Operation of SMU/
Silo
Track
™ System
See Bulletin 344D(
Silo
Track
V 1.0) or 344G(
Silo
Track
V 2.0)
or Bulletin 344J(
Silo
Track
V 3.X).
Fuse Replacement
The fuses incorporated into the SMU PCBs are not intended for
operator replacement. Direct access to the fuses is restricted. A
qualified technician can replace the applicable fuse(s) according
to the following specifications. If necessary, consult the factory
for additional technical assistance or for return of SMU.
115VAC
F1: 5x20mm, 0.63A Time Lag (Slo-Blo), 250VAC
LittelFuse #218.630 or Bussmann #GDC-630mA
F2, F3: 5x20mm, 0.2A Time Lag (Slo-Blo), 250VAC
LittelFuse #218.200 or Bussmann #GDC-200mA
230VAC
F1: 5x20mm, 0.315A Time Lag (Slo-Blo), 250VAC
LittelFuse #218.315 or Bussmann #GDC-315mA
F2, F3: 5x20mm, 0.1A Time Lag (Slo-Blo), 250VAC
LittelFuse #218.100 or Bussmann #GDC-100mA
MAINTENANCE
