General Specifications
2-6 Accusonic Model 7720 Flowmeter
Data Display on Hand-held Terminal
In normal operation, 11 different display screens are available, one for each variable as follows:
Envelope Times, Travel Times, Time Differences, Signal Gains, Velocities,
Flow, Volume, Level, Temperature, Sum of the Section Flows & Volumes, Analog in.
The first five are for diagnostic purposes concerned with the water velocity determinations, the next five for
observing flow data, and the last for diagnostic purposes concerned with the various Level inputs.
For details of the displays, see the section on Data displays at the end of Chapter 5.
For definitions of the variables, see the section on “Variables” at the end of Chapter 7.
Parameter Insertion and Reading, Hand-held Terminal
Parameters describing the flowmeter configuration are inserted using 7 different parameter menus. These are:
SYSTEM, SECTIONS, PATHS, LEVEL INPUTS, ANALOG OUTPUTS, RELAYS, LOGGING.
For instructions on how to insert the parameters, see Chapter 5.
For details on setting up the internal data logging, see Chapter 5.
For details of the parameters, see the section on “User Defined Parameters” in Chapter 7.
There are two command menus:
MEASURE: To put the flowmeter into the normal “Measure” mode.
SYSTEM ACTIONS Under which any of the following three commands may be made.
STORE ALL PARS: To store parameters once they have been entered correctly.
RESTORE ALL PARS: To recall the stored parameters from non-volatile memory.
XMIT PARAMETERS: To transmit the complete parameter list to a data terminal.
In addition there is a list called SYSTEM STATS, which contains the software revision number, a parameter to
change the data baud rate to the Hand-held terminal, and the facility to change the real time clock.
Connection of a PC in place of Hand-held Terminal
A PC or other terminal with ANSI emulation may be connected to the 9 pin “Hand-held Communications”
socket, as an alternative to the Hand-held terminal usually supplied. The same logic of operation and functions
will be available. A “Null Modem” cable or standard serial cable with a “Null Modem adapter” is required to
interconnect between this socket and a PC’s serial port. Either the cable or adapter can be purchased at a PC
supply or electronics store.
RS232 signals: 19200 baud, 8 data bits, No parity, 1 Stop bit, No handshaking protocol
The baud rate may be changed using a parameter under SYSTEM STATS.
The connections on the 9 pin D socket are:
Pin 2. Data into the 7720 unit
Pin 3 Data out from the 7720 unit
Pin 5 Common, connected to ground in the 0Plus unit.
Pin 9 +5 volts dc. (for power to the Hand-held terminal).
The following ASCII characters are recognized by the flowmeter.
Numbers 0 through 9, Enter, Esc, – sign, Decimal point, #, Letters U, D, L, R, P, S, T, M, Z
The letters U, D, L, R, are used as cursor controls, ↑, ↓, ←, →
# or S is used to cause a system Reset,
P to put the system in Pause,
T to prevent updating of the Terminal display
M to put the system in the Measure mode
Z as an alternative for Esc