Max Machinery 121 INDICATOR - Manual (Page 7)

Specifications
121-000-350 © 2001 Max Machinery, Inc. Pg 7
comparison is now made by comparing the
current flow rates against the specified hi and
low limits.
Step 7: Compute the Analog Output-This designated
flow rate value is now used to compute the
analog output.
Step 8: Compute the Flow Totals by Summation-A
flow total increment is computed for each flow
rate. This increment is computed by multiplying
the respective flow rate by a time base scaler and
then summing. The totalizer format also includes
provisions for total rollover.
Step 9: Total Preset Comparisons-The total associated
with a preset function is then compared
against the corresponding preset value and any
required control actions taken.
Step 10: Pulse Output Service-The pulse output is next
updated by scaling the total increment which has
just been determined by the pulse output scaler
and summing it to any residual pulse output
amount.
Step 11: Update Display and Printer Output-The
instrument finally runs a task to update the
various table entries associated with the front
panel display and serial outputs.
Setup Mode
The setup mode is password protected by means
of a numeric lock out code established by the
user. In addition, a secret, manufacturer ’s
numeric unlock entry sequence is available.
The system also provides a minimum
implemetation of an “audit trail” which tracks
significant setup changes to the unit. This feature
is increasingly being found of benefit to users or
simply required by Weights and Measurement
Officials in systems used in commerce, trade, or
“custody transfer” applications.
A Worksheet is provided to assist the user in
setting up the instrument. In addition, a software
program is available which runs on a PC using a
RS-232 Serial connection to the Flow
Computer. Illustrative examples may be down
loaded in this manner.
The setup mode has numerous subgrouping of
parameters needed for flow calculations. There
is a well conceived hierarchy to the setup
parameter list. Selections made at the
beginning of the setup affect offerings further
down in the lists.
In the setup mode, the flow computer
activates the correct setup variables based on
the instrument configuration, the flow
equation, and the hardware selections made
for the compensation transmitter type, the
flow transmitter type, and meter
enhancements (linearization) options
selected. All required setup parameters are
enabled. All setup parameters not required
are suppressed.
A help line prompt is provided for each entry.
In addition a help message is available which
may be accessed by depressing the “HELP”
key.
In the setup mode selections, several parameters
are required to be input by the operator
since these parameters are blank when the
unit is received. The user will be prompted
for these necessary values for his application.
A blank parameter will prevent the user from
entering the run mode and a suitable warning
message will be issued.
Also note that in the setup mode there are
parameter selections which have preassigned
industry standard values. The unit will assume
these values unless they are modified by the
user.
Most of the process input variables have
available a “default” or emergency value
which must be entered. These are the values
that the unit assumes when a malfunction is
determined to have occurred on the
corresponding input.
Hint: It is possible to enter in a nominal constant
value for temperature or density, or analog
flow inputs by placing the desired nominal
value into both the lo and hi values. This is
also a convenience when performing bench top
tests without simulators.
Maintenance Mode:
The Maintenance Mode of the 121 Series is the
Test and Calibration Mode for the device. This
mode provides a number of specialized utilities
required for factory calibration, instrument
checkout on start-up, and periodic calibration
documentation.
A password is required to gain access to this
specialized mode of operation. Normally