GE PanaFlow XMT1000, User Manual

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PanaFlow™ XMT1000 User’s Manual 15
Chapter 2. Programming
2.4 Glossary of Terms
•
Backlight:
The LCD display backlight has three user-adjustable parameters. The brightness, the contrast, and the
length of inactivity which triggers automatic shutdown can be individually set within available limits.
•
Error Handling:
The manner in which various XMT1000 outputs respond to automatically generated system errors
can be set by the user by selecting the options from a drop-down list.
•
Frequency Output:
In frequency mode, the digital output generates a pulse with a frequency that is proportional to
the magnitude of the measured flow parameter (e.g., 10 Hz = 1ft
3
/hr).
•
HART: HART is a serial communication protocol used for industrial automation. Its main advantage is that it can
communicate over 4-20 mA analog instrumentation current loops over the pair of wires used by the analog only
host system.
•
K-Factor: To calibrate the XMT1000 against a reference value, the raw flow velocity readings may need to have a
correction factor applied. This K-Factor can be a single constant or a table of K-Factor vs. Velocity values.
•
Loop Powered: Loop powered analog devices use the power provided by the meter itself rather than by an external
power supply. This results in a simple 2-wire connection between the meter and the external device.
•
Mass Flow: Mass flow is the mass of fluid passing the measurement point in a given period of time. This value is
calculated by the meter from the measured flow velocity and the programmed pipe and fluid parameters.
•
Modbus:
Modbus is a serial communication protocol developed by Modicon
®
for use with its programmable logic
controllers. It is a method used for transmitting information over serial lines between electronic devices.
•
Pulse Output:
In pulse/totalizer mode, the digital output generates a pulse with a width corresponding to one unit
of the measured flow parameter (e.g., 1 pulse = 1 ft
3
).
•
Reynolds Correction:
When turned on, a factor based on the kinematic viscosity and the flow rate of the fluid is
applied to all measurements. Reynolds correction should be On for most applications.
•
Serial Port Settings:
When the XMT1000 serial port is connected to an external serial device, communication
between the two devices only occur if the serial port settings of the two devices match. These settings include:
baud rate , data bits , stop bits , and parity .
•
Special Transducer:
If your transducer has no number engraved on the body, select
SPECIAL
in the Transducer
Number menu.
•
Tw:
The TW parameter is the time the transducer signal spends traveling through the transducer body and the
transducer cable. This value must be subtracted from the total signal transit time to calculate the actual signal
transit time only through the fluid.
•
Totalizer:
The totalizer accumulates a running total of the amount of fluid which passes the measurement point
between specified start and stop times.
•
Tracking Window:
The tracking window is used to detect the receive signal when you are unsure of the fluid
sound speed. For the XMT1000 flow transmitter, the Tracking Window is always ON.
•
Zero Cutoff:
When the measured flow rate is below the zero cutoff value, the display is forced to 0.00. This is to
avoid rapid fluctuations in the reading whenever the flow rate is close to zero.