90
Analog Signal Resolution Affected by Scale Factor
The analog signals range from –5 volts to +5 volts, resulting in a total range of 10 volts.
With the standard Remote Access option available, all analog output signals are at full
scale (full scale being the default). Full scale for torque as an example is –512 ft-lb to
+512 ft-lb (-696 to +696 Nm), for a total range of 1024 ft-lb (1392 Nm). This results in
an output resolution scale factor as follows:
1024 ft-lb (1352 Nm) = 10 volts, where
1 ft-lb (1.36 Nm) = 9.8 milli-volts
9.8 milli-volts is well below the signal noise rated for this port, therefore it is not
possible to see 1 ft-lb increments on this analog signal. The utility provides scaling
options separately for all three analog signals; therefore, if typical usage is well below
the maximum levels, 1 ft-lb (1.36 Nm) increments can be seen on typical analog
monitoring equipment. For example, applying a range of +/- 0 to 64 ft-lb (87 Nm), the
output resolution scale factor would look as follows:
128 ft-lb (174 Nm) = 10 volts, where
1 ft-lb (1.36 Nm) = 9.8 milli-volts
78.1 milli-volts is well above the worst case of signal noise (15 – 35 mV); therefore,
increments as low as ¼ to ½ ft-lb (0.34 to 0.68 Nm) can be seen reliably.
Operating Modes
The Output Frequency, or update rate, controls how frequent the system will change the
analog outputs. The highest update rate is 2,000 times per second, which is the default.
If this high frequency is not needed or causing problems with the monitoring
equipment, the update rate can be lowered. Every time the analog signals are output,
the synchronization signal is pulsed also. Therefore, the update rate controls how
frequent the synchronization signal is pulsed.
The Output Mode selects the state in which the analog signal outputs are updated.
The options are as follows:
On Always – Always output regardless of current operational state.
Off (disabled) – Totally shuts down the analog signal outputs.
Auto, when active – Is automatically on when the system is in an active state; meaning
not STOP’ed and not in HOLD.
On START command – Synchronizes the analog signal output with the START
command, ensuring the output is performed only during the trials exercised.
To Next Page
Loading...
