Rice Lake MSI-9750A CellScale RF Portable Indicator - Manual (Page 15)

MSI CellScale ® System • 9750A User Guide Page 15
MEASUREMENT SYSTEMS INTERNATIONAL
Firmware Version 5-XX for 2450 Modems
Transmit power set to HI.
Time out set to 10 seconds.
My Address remains unchanged and is the same in any network.
TROUBLESHOOTING RF CONNECTION PROBLEMS
Most connection problems are caused by improperly set up RF Networks. Both the 9750A and the master CellScale
unit must have identical Network numbers. In addition, the CS Address must match on both units. If the Net-
work and/or CS Address of the CellScale is in question, you might have to connect a terminal to the CellScale to
determine its exact settings. See the CellScale manual for this procedure. Verify the 9750A settings are proper
by using the “CONFIGURE RF MODEM” procedure. Each slave device (9750As, 3750CS, and 9020s) must
have unique “My Address”.
A common cause of perceived problems is the “Phantom Network”. This occurs when there is a confl icting Net-
work within broadcast range. Multi-CellScale sites must be planned carefully so that there are never two master
CellScales on the same Network within range of each other. Since the CellScale can broadcast for miles with
good LOS (line of sight) conditions, this consideration is very important. If you suspect your 9750A has locked
on to a distant (Phantom) network, try switching both the master CellScale and the 9750A slave to another unused
Network. MSI advises avoiding Network #0 when possible, as this is the Modem default, and therefore most
likely to be found on units that were left in default settings.
Weight displays, but 9750A keys don’t work
This is a result of changing the CS Address in the slave 9750A so it no longer matches the master CellScale. The
modem is still registered by the master CellScale, but control codes are not received because the master assumes
the codes are intended for a different slave CellScale. Change the CS Address in the 9750A back to the number
that matches the master CellScale.
Unit goes in and out of communication
This is usually a result of being in or near an “RF Null” zone. Because of multiple echoes of signals there is
sometimes locations that are particularly problematic even for Frequency Hoppers. Usually moving the antenna
location even a small distance can clear up this kind of problem. Avoid placing the antenna up against large metal
walls. Concrete walls can also be problematic due to their high moisture content. The antenna should be at least
4 inches away from large metal or concrete surfaces. Mounting the antenna too close to a wall has the effect of
making the Antenna directional and can attenuate the output.
Range is Inadequate
Antenna placement is the most common cause of poor range. Check that the RF power level of the master and
slave units is on “High”. Radio signals in nearby bands that have signifi cant power can also reduce range. Lon-
gest range will always be achieved by Line-of-sight (LOS) antenna placement. Any obstacle that interferes with
LOS will reduce the range. Signifi cant blocking is caused by metal buildings, solid concrete walls, and any other
object that has fairly high electrical conductance. Raising the master antenna higher can help. Just moving the
relative antenna placement a short distance might fi nd an RF “path” that will improve distance. The CellScale
can sometimes take advantage of refl ecting surfaces to get around obstacles. CellScale device antennas should
always be placed in vertical polarization; that is the shaft of the antenna should be perpendicular to the earth,
not parallel. It is OK to mount the Antenna upside down. This is a good solution when an antenna is mounted on
the ceiling for communication with CellScale components in the building. The 9750A internal antenna is mildly
directional. Aim the end of the 9750A towards the CellScale master for longest range. In short range applications
(LOS and <500 feet) the 9750A is essentially omni-directional.
Some CellScale master units can take advantage of higher gain antennas.Yagi Antennas can greatly improve the
range of a CellScale system when installed on the master CellScale. These multi-element antennas are highly
directional and must be aimed towards the 9750A area of operation.
The CellScale system is designed using state of the art RF Modems. However there will be conditions and envi-
ronments where communication of telemetry is sporadic or impossible. Jamming of FHSS systems is diffi cult,
but not impossible. Bear in mind that the most likely source of jamming will be other CellScale systems on the
same network, within transmission range. The new breed of wireless phones (not Cell Phones) operating in the
2.4GHz bands will not jam a CellScale. However the CellScale may be received on the wireless phone and will
sound like a background ticking noise. Standard Cell Phones do not operate in the same bands as the CellScale and
will not interfere with CellScale components. However, a Cell Phone repeater tower nearby might have enough
out of band interference to reduce the range of CellScale equipment.