Sensaphone SCADA 3000 Users manual - Manual (Page 47)

5-1
Chapter 5: Input Wiring
Chapter 5: INPUT WIRING & CONFIGURATION
The SCADA 3000 is compatible with a wide variety of electrical signal sources including con-
tacts, 10K thermistors, analog voltage outputs and 4–20mA current sources. Each type of sig-
nal requires the configuration jumpers, located behind the input terminal strip, to be installed
in the proper position for each type of signal. Follow the instructions below to properly wire
and configure the inputs for each type of electrical signal. Note: Needlenose pliers will be
required to move the jumpers.
Warning: The inputs are designed to work with low voltage signals from 0–5V.
DO NOT connect differential voltages greater than 5V to the inputs. DO NOT
connect 120VAC to the inputs. In the 4–20mA jumper position and when no
jumper is installed, the inputs are differential and will work with signals that are
+/-12V away from power supply ground. This allows the use of multiple 4–20mA
circuits on one loop. See circuit schematics for more information.
General Wiring Considerations
Most dry contact sensors can be connected to the SCADA 3000 using inexpensive 2-conduc-
tor twisted-pair cable as small as #24 AWG. For thermistor, 0–5V and 4–20mA sensors, use the
wire chart below as a reference for selecting the appropriate wire gauge. Note that if the sen-
sor is located far from the unit or if you are running cable in an electrically noisy environment,
you should seriously consider using twisted pair shielded cable. This will shield the signal from
electrical interference, thereby preventing false readings and/or damage to the unit. If you are
using shielded cable, connect the shield to the EG pin on the unit. To minimize electrical noise
coupling between I/O lines, follow the guidelines listed below for routing your wires:
• Route the power supply and communications cables to the unit by a separate path
from wiring to I/O devices. Where paths must cross, their intersection should be
perpendicular.
• Do not run signal or communications wiring and power in the same conduit.
• Segregate I/O wiring by signal type. Bundle wiring with similar electrical charac-
teristics together.
• Allow at least two inches between the unit and I/O wiring ducts.
Wiring Minimum
Distance Wire Gauge
700' #24 AWG
1500' #22 AWG
2500' #20 AWG
Terminal Blocks
The terminal blocks for wiring the inputs (and outputs) are removable. They should only be
removed or attached when power to the SCADA 3000 is OFF. If for instance you had to return
your SCADA 3000 for service, you could remove the terminal blocks in order to maintain your
current wiring configuration. To remove terminal blocks use your thumb or forefinger to push
the screw section of the block straight out. (See Figure 1)