2-6 / Installation 2808B
2.5 WIRING OF 1-5V SIGNAL/POWER LOOP
The 1-5V signal/power loop can be powered in two ways, by the receiving device (controller,
recorder, etc.), or by an external supply. Provide a setup similar to that shown in either
Figure 2-4 or 2-5. Apply +24V across the + and - terminals of the Transmitter as shown,
whether supplied by an external supply, or by the receiving device. Next, connect the 1-5V
output, or the terminal block labeled V to the input of the device. Notice: Unlike the current
loop, this input must be analog ground referenced, and not passed through a sampling
resistor.
Signal Shielding: Use twisted, three-wire, shielded cable covered by insulating material for
the signal/power wiring. For further information regarding signal shielding, consult section
2.4.
2.6 EFFECTS OF LEAD & LOAD RESISTANCE & SUPPLY
VOLTAGE
The total loop resistance consists of the load (loop resistor) plus the resistance of both
conductors in the signal/power loop. For any given power supply voltage, the total loop
resistance must be kept within the specified limits. The graphs of Figures 2-6 and 2-7
illustrate the minimum and maximum loop resistance that may be used with various
supply voltages for models with and without digital indicators.
Figure 2-6 - Transmitter without Digital Indicator
To Next Page
Loading...
