Max Machinery 290 Series Frequency (269, 294 and 295) - Manual (Page 7)

7 IH 295-000-350 • rev. 6/2011 • ©2010-11 Max Machinery, Inc.
Rotation/Output Indicators
All of the microprocessor based transmitters incorporate a LED to indicate that they are producing a
pulse output and/or detecting magnet rotation in the meter.
An alternating red/green or blue/green LED indicates that the circuit is detecting a rotating
magnet and should provide an output. Additional LED’s are present for setup, programming and
troubleshooting and are not intended for general use.
Note: There are no selections or adjustments to be made on the circuit board. The only method of
altering the setup parameters is through the serial interface program.
Contact the factory regarding
P/N 294-100-050, user interface software.
Field Compensation of transmitter
When a new transmitter is attached to a flow meter, the compensation routine should be performed
to optimize the performance of the system. This routine requires a steady flow rate which turns
the meter at between 15 and 1000 RPM. If you are using the interface software, please consult the
“software Interface” manual for instructions. For the Model 295 and 296, the sequence is as follows:
1. Stabilize the flow rate
2. Push the compensation button on the PCA
3. The blue/green LED will change to solid blue for 6 to 8 revolutions of the meter
4. A green indicator light indicates a successful update of the compensation, a red indicator light
indicates that the previous compensation has been retained.
High Temperature Operation Above 65°C (150°F)
The operating limit of the meter/transmitter is a function of both the ambient and the metered fluid
temperature, as shown in the following graphs. Although the electronic components are rated to
80°C (175°F), additional heat can be conducted from the flow meter into the transmitter housing
requiring a lower ambient temperature limit for high fluid temperatures.
To prolong the life of the transmitter and reduce the risk of component related failures over time,
high ambient temperatures >65°C (150°F) should be avoided if possible. It is a good idea to locate
the transmitter away from hot spots such as steam pipes, ovens and heaters. When working with
elevated fluid temperatures >65°C (150°F), insulating the flow meter is recommended to reduce the
risk of burns, and to reduce the heating of the electronics by convection of hot air off of the meter
(especially for larger meters). The upper temperature limits shown in the curves rely on ambient
convection to remove heat from the transmitter housing, cooling the electronics. For this reason,
if operating near the upper temperature limit, the transmitter should not be insulated. At these
elevated temperatures, the transmitter will be very hot — exercise appropriate caution.