b
c
Remote Calibration Check
.
The instrument can be placed in the calibration mode
(positive or negative) by shorting terminals Power Common and SHP for positive or SHN for
negative on the lower I/O connector. Figure 4 indicates two methods of remotely
entering the calibration mode (external switch, or push button control). The
Remote Cal function provides a convenient method of periodically monitoring
calibration of the instrument in the positive or negative realm.
Master/Slave Connections.
When more than one 5M78 is being used in a measurement
setup (instruments are closely mounted or the transducer cabling is in a common conduit
or raceway), beat frequencies may be produced from the 3-kHz oscillators used in
the instruments to develop the excitation. To prevent beat frequencies from occur-
ring, one unit can be designated the master, and the remaining units can be driven
from the oscillator contained in the master unit. The remaining units are designated
as slave instruments. To perform master/slave wiring, refer to Figure 7.
3.
CALIBRATION
(cont.)
Switch 1 - Mode
- selects current (I) or voltage analog output
Switch 2 - Volts
- s/- 5 or +/- 10 Vdc when mode is voltage
Switch 3 - Current
- selects 4-12-20 or 4-20mA when mode is current
Switch 4 - Filter
- selects 650 Hz or 100 Hz at 3 db, for 100 Hz switch 5 must be set to the right
Switch 5 - Filter
- selects 10 Hz or 100 Hz at 3 db, for 100 Hz switch 4 must be set to the right
Switch 6 - Sync
- selects excitaton clock to slave from a master module or to be master
Switch 7 - Zero Adj.
- selects extended (100%) or normal (25%) zero authority
Switch 8 - Aux Output
- selects SYNC terminal output for use by other linked modules
Coarse Zero
- 16 position switch adjustment for stepped zero balance control
marked for calibration default position
Fine Zero
- 18 turn potentiometer for fine zero balance control
Coarse Span
- 16 position switch adjustment for stepped gain contr ol
marked for calibration default position
Fine Span
- 18 turn potentiometer for fine gain - span control
Symmetry
- adjust the negative output span to be equal to the positive output
Phase
- adjustment for phasing the AC modulated signal to its highest level at load
Over Range
- indicates when the analog output is 2% greater than mode selected
Power
- indicates the power input voltage is ON
Fig. 2 Front Panel Settings and Indicators
Calibraton 5M78.3
or in the AUX position
for raw - uncalibrated
analog
gained
voltage output
