Dynasonics TFX Ultra Transit Time Flow Meters - Manual (Page 50)

CH PSWD? — Change Password (Value)
0…9999
The password comes from the factory set to 0000. When set to 0000 the password function is disabled. By changing the
password from 0000 to some other value (any value between 0001…9999), configuration parameters will not be accessible
without first entering the password value when prompted. If the value is left at 0000, no security is invoked and unauthorized
changes can be made. Access to resetting of the totalizer is also protected by this password. If the password is lost or
forgotten, contact the manufacturer for a universal password to unlock the meter.
SER MENU – SERVICE MENU
The SER MENU menu allows access to meter set up values that may need revision due to application specific conditions and
information valuable in troubleshooting.
SSPD mps — Liquid Sound Speed (Meters per Second) (Reported by Firmware)
SSPD fps — Liquid Sound Speed (Feet per Second) (Reported by Firmware)
The flow meter performs an actual speed of sound calculation for the liquid it is measuring. This speed of sound calculation
will vary with temperature, pressure and fluid composition.
The meter will compensate for fluid sound speeds that vary within a window of ± 10% of the liquid specified in the BSC MENU.
If this range is exceeded, error code 0011 will appear on the display and the sound speed entry must be corrected.
The value indicated in SSPD measurement should be within 10% of the value entered/indicated in the BSC MENU item
FLUID SS. (The SSPD value itself cannot be edited.) If the actual measured value is significantly different (> ± 10%) than the
BSC MENU’s FLUID SS value, it typically indicates a problem with the instrument setup. An entry such as FL TYPE, PIPE OD or PIPE
WT may be in error, the pipe may not be round or the transducer spacing is not correct.
Table 10 lists sound speed values for water at varying temperatures. If the meter is measuring sound speed within 2% of the
table values, then the installation and setup of the instrument is correct.
Temperature Velocity Temperature Velocity Temperature Velocity
° C ° F mps fps ° C ° F mps fps ° C ° F mps fps
0 32 1402 4600 80 176 1554 5098 160 320 1440 4724
10 50 1447 4747 90 194 1550 5085 170 338 1412 4633
20 68 1482 4862 100 212 1543 5062 180 356 1390 4560
30 86 1509 4951 110 230 1532 5026 190 374 1360 4462
40 104 1529 5016 120 248 1519 4984 200 392 1333 4373
50 122 1543 5062 130 266 1503 4931 220 428 1268 4160
60 140 1551 5089 140 284 1485 4872 240 464 1192 3911
70 158 1555 5102 150 302 1466 4810 260 500 1110 3642
Table 10: Sound Speeds for water
SIG STR — Signal Strength (Reported by Firmware)
The SIG STR value is a relative indication of the amount of ultrasound making it from the transmitting transducer to
the receiving transducer. The signal strength is a blending of esoteric transit time measurements distilled into a usable
overall reference.
The measurement of signal strength assists service personnel in troubleshooting the flow meter system. In general, expect
the signal strength readings to be greater than five on a full pipe with the transducers properly mounted. Signal strength
readings that are less than five indicate a need to choose an alternative mounting method for the transducers or that an
improper pipe size has been entered.
Signal strength below the low signal cutoff SIG C-OF value will generate a 0010 error (Low Signal Strength) and require either
a change in the SIG C-OF value or transducer mounting changes.
SER MENU – SERVICE MENU
Page 50 March 2014