Dynasonics TFX Ultra Transit Time Flow Meters - Manual (Page 51)

OTE:
N
If the unit is configured to display totalizer values, the display will alternate between error 0010 and the
totalizer value.
Signal strength readings in excess of 98 may indicate that a mounting method with a longer path length may be required.
For example, if transducers mounted on a 3 inch PVC pipe in V-Mount cause the measured signal strength value to exceed 98,
change the mounting method to W-Mount for greater stability in readings.
Because signal strength is not an absolute indication of how well a meter is functioning, there is no real advantage to a signal
strength of 50 over a signal strength of 10.
TEMP 1 — Temperature of RTD 1 (Reported by Firmware in °C)
When RTD is selected from the CH2 menu and RTDs are connected to the energy meter, the firmware will display the
temperature measured by RTD 1 in ° C.
TEMP 2 — Temperature of RTD 2 (Reported by Firmware in °C)
When RTD is selected from the CH2 menu and RTDs are connected to the energy meter, the firmware will display the
temperature measured by RTD 2 in ° C.
TEMPDIFF — Temperature difference (Reported by Firmware in °C)
When RTD is selected from the CH2 menu and RTDs are connected to the energy meter, the firmware will display the
difference in temperature measured between RTD 1 and RTD 2 in ° C.
SIG C-OF — Low Signal Cutoff (Value)
0.0…100.0
The SIG C-OF is used to drive the flow meter and its outputs to the SUB FLOW (Substitute Flow described below) state if
conditions occur that cause low signal strength. A signal strength indication below 5 is generally inadequate for measuring
flow reliably, so the minimum setting for SIG C-OF is 5. A good practice is to set the SIG C-OF at approximately 60…70% of
actual measured maximum signal strength.
OTE:
N
The factory default Signal Strength Cutoff is 5.
If the measured signal strength is lower than the SIG C-OF setting, an error 0010 will be shown on the flow meters display until
the measured signal strength becomes greater than the cutoff value.
A signal strength indication below 2 is considered to be no signal at all. Verify that the pipe is full of liquid, the pipe size and
liquid parameters are entered correctly, and that the transducers have been mounted accurately. Highly aerated liquids will
also cause low signal strength conditions.
SUB FLOW — Substitute Flow (Value)
0.0…100.0
Substitute Flow SUB FLOW is a value that the analog outputs and the flow rate display will indicate when an error condition
in the flow meter occurs. The typical setting for this entry is a value that will make the instrument display zero flow during an
error condition.
Substitute flow is set as a percentage between MIN RATE and MAX RATE. In a unidirectional system, this value is typically set
to zero to indicate zero flow while in an error condition. In a bidirectional system, the percentage can be set such that zero
is displayed in a error condition. To calculate where to set the substitute flow value in a bidirectional system, perform the
following calculation:
100
100
-
-
=
Maximum Flow
Substitute Flow
Maximum Flow Minimum Flow
Table 11 lists some typical settings to achieve zero with respect to MIN RATE and MAX RATE settings.
OTE:
N *The software utility is required to set values outside of 0.0…100.0.
SER MENU – SERVICE MENU
Page 51 March 2014