'
If the device to be controlled is a pilot light or relay, the negative (-) side of the load will be con-
nected to the One Series output connection.
For Model A, this would be the Orange, 20 AWG wire.
For Models B & C, the terminal is marked IAW output.
The positive side of the load is connected to the positive side of the power source V+.
See Diagram 5.
NOTE: If the IAW load is inductive (e.g., a relay), a fly back diode, such as a 1N914 should be
used to prevent electrical spikes into the switched output circuit. See Diagram 6.
For model D1D (VAC powered), the IAW switch 5 to 30 VDC power must be supplied externally.
Wire the positive side of the "load" to the power supply and the negative side to the terminal marked
IAW on TB1 per Diagram 3.
Logic Solver Connection For IAW Output
If the One Series IAW output is connected directly to a digital input channel on the logic solver,
an appropriately sized pull-up resistor may be required (see note) between the digital input and
a DC power source. The value of the pull-up resistor must be calculated based on the excitation
voltage and the voltage threshold for a logic level low required by the logic solver. See Diagram 7.
NOTE: Some logic solver inputs already include a pull-up resistor or circuit. Consult United Electric for
flow charts, state diagrams and timing charts for the IAW output when interfacing with a logic solver.
Optional 4-20 mA Analog Process Signal Output
The One Series 4-20 mA output signal is intended for remote monitoring or trending of the
process variable. The output is a sourcing output which is powered from the One Series VDC
power. It does not use a separate loop power supply, which simply means, no external power
supply should be applied to this connection.
The One Series sources current to the load, indicator, controller or an analog input of a logic
solver. See diagram 12 and 13. One side (positive, +) of the load (500
Ω
max.) is connected to
the 4-20mA output and the other side should be returned to the One Series common
(to complete the circuit loop).
4-20 mA connections to positive side of the load circuit:
n
For Model A, this would be the Yellow, 20 AWG wire.
n
For Models B & C, the terminal is marked 4-20 mA.
n
For Model D, the terminal is marked TB1 and labelled 4-20 mA
The Negative (-) lead of the load circuit must return to the One Series circuit common connection.
