Max Machinery 121 INDICATOR - Manual (Page 6)

Pg 6 121-000-350 © 2001 Max Machinery, Inc.
Specifications
Pulse Inputs:
Number of Flow Inputs: one
Configurations supported: single input with or
without quadrature (menu selectable)
Input Impedance: 10 K nominal
Pullup Resistance: 10 K to 5 VDC (menu selectable)
Pull Down Resistance: 10 K to common
Trigger Level: (menu selectable)
High Level Input
Logic On: 3 to 30 VDC
Logic Off: 0 to 1 VDC
Low Level Input (mag pickup)
Selectable sensitivity: 10 mV & 100 mV
Minimum Count Speed: User selectable
Maximum Count Speed: Selectable: 0 to 20kHz
Overvoltage Protection: 50 VDC
Fast Transient: Protected to 500 VDC
(Capacitive Clamp)
Relay Outputs
The relay outputs are menu assignable to (individually
for each relay) Low Rate Alarm, Hi Rate Alarm,
Prewarn Alarm, Preset Alarm, Pulse Output (pulse
options) or General purpose warning (security).
Number of relays: 2
Contact Style: Form C contacts
Contact Ratings:
250 VAC @ 5 amps
30 VDC @ 5 amps
Fast Transient Threshold: 1000 V
Serial Communication
The serial port can be used for printing, datalogging,
modem connection and communication with a computer.
Analog Output
The analog output is menu assignable to correspond
to the Uncompensated Volume Rate, Corrected
Volume Rate, Mass Rate, Temperature, Density,
Volume Total, Corrected Volume Total or Mass Total.
Type: Isolated Current Sourcing
Isolated I/P/C: 500 V
Available Ranges: 4-20 mA, 0-20 mA
Resolution: 12 bit
Accuracy: 0.05% FS at 20 Degrees C
Update Rate: 1 update/sec minimum
Temperature Drift: Less than 200 ppm/
O C
Maximum Load: 1000 ohms (at nominal line voltage)
Compliance Effect: Less than .05% Span
60 Hz rejection: 40 dB minimum
EMI: No effect at 3 V/M
Calibration: Operator assisted Learn Mode
Averaging: User entry of DSP Averaging constant
to cause a smooth control action.
Isolated Pulse output
The isolated pulse output is menu assignable to
Uncompensated Volume Total, Compensated
Volume Total or Mass Total.
Isolation I/O/P: 500 V
Pulse Output Form: Open Collector
Maximum On Current: 125 mA
Maximum Off Voltage: 30 VDC
Saturation Voltage: 1.0 VDC
Maximum Off Current: 0.1 mA
Pulse Duration: User selectable
Pulse output buffer: 8 bit
Pulse Rate Averaging: Standard
Fault Protection
Reverse polarity: Shunt Diode
Transient Protection: 500 VDC (Capacitive Clamp)
Operating Mode
The Flow Computer can be thought of as making a
series of measurements of flow, temperature/
density sensors and then performing calculations
to arrive at a result(s) which is then updated
periodically on the display. The analog output,
the pulse output, and the alarm relays are also
updated. The cycle then repeats itself.
Step 1: Update the measurements of input signals-
Raw Input Measurements are made at each
input using equations based on input signal
type selected. The system notes the “out of
range” input signal as an alarm condition.
Step 2: Compute the Flowing Fluid Parameters-The
temperature, viscosity, and density equations
are computed as needed based on the flow
equation and input usage selected by the
user.
Step 3 : Compute the Volumetric Flow-Uncompensated
flow is the term given to the flow in volume
units. The value is computed based on the
flowmeter input type selected and augmented by
any performance enhancing linearization that has
been specified by the user.
Step 4: Compute the Corrected Volume Flow at
Reference Conditions-In the case of a corrected
liquid volume flow calculation, the corrected
volume flow is computed as required by the
selected compensation equation.
Step 5 : Compute the Mass Flow-All required
information is now available to compute the
mass flow rate as volume flow times density.
Step 6: Check Flow Alarms-The flow alarm functions
have been assigned to one of the above flow
rates during the setup of the instrument. A