AMETEK ReFlex - Manual (Page 192)

ReFlex Power™ Fixed Power DC Power Supply
M380056-01 Rev J 5-23
The voltage drop (per output or return lead) could be calculated using the
following equation:
V = I x L x R20°C x [1 + 0.004 x (T - 20°C)]
where,
V = total voltage drop, V
I = current, A
L = length of wire, m
R20°C = resistance of wire,
Ω/m, at 20°C
T = temperature of wire conducting current, °C
N OISE AND I MPEDANCE E FFECTS
To minimize noise pickup or radiation from load circuits, load wires and
remote sense wires should be twisted-pair with minimum lead length.
Shielding of the sense leads may be necessary in high noise environments.
Even if noise is not a concern, the load and remote sense wires should be
twisted-pairs to reduce coupling between them, which could impact the
stability of the output converter. If connectors are utilized for the power and
sense leads, be careful not to introduce coupling between the leads. Ensure
that the connector terminals for the sense leads are in adjacent locations, and
minimize the physical loop area of the untwisted portions.
Twisting the load wires provides an additional benefit in reducing the parasitic
inductance of the cable. This improves the dynamic response characteristics
at the load by maintaining a low source impedance at high frequencies. Also,
with long load wires, the resultant inductance and resistance could produce
high frequency voltage fluctuations at the load because of current variations
in the load itself. The impedance introduced between the output of the power
supply and the load could make the ripple/noise voltage at the load worse
than the specification of the FPDC power supply module (which is valid when
measured at the front panel connector) because of the contribution to the
ripple/noise by the load current. Additional filtering with bypass capacitors at
the load terminals may be required to bypass the high frequency load
currents.
5.5 OPERATION
The FPDC power supply module functions under remote control through a host
controller or directly from control at its User Interface Connector. The ReFlex
Power™ Controller module serves as a communications portal between the
power supply modules and the remote host controller. All aspects of operation
could be achieved through use of commands that comply with the requirements
of the SCPI Standard 1999 command language. Additional discrete digital control