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Cavro® XLP 6000 Modular Syringe Pump Operating Manual, 734237-C, en
2 - Hardware Setup
Power and Electrical Considerations
A current-limiting power supply is recommended. Current limiting above 1.0A is
acceptable, assuming that no additional equipment is operated from the supply.
If the power supply uses current feedback, the time-current foldback point must be
sufficient to allow charging of a 470
µ
F capacitor without folding back. If an
external capacitor is used, exercise care to ensure that the supply always starts
after foldback, particularly at low AC line voltage.
2.1.2
Integrating a Power Supply
When a power supply is used to operate more than one XLP 6000 or other device,
it must provide the total average current for all devices. The power supply and
filter capacitance together must satisfy the total peak input current for all devices.
For example, if a system incorporates six XLP 6000 pumps with other equipment
that together require 4 amps, a 10A power supply is satisfactory, provided the
output filter capacitance in the supply is at least 10,000
µ
F:
6 x 0.85 = 5.1A; +4A = 9.1A (choose a 10A power supply)
If the power supply filter capacitance is less than 10,000
µ
F, use either additional
external capacitance or a 15A power supply:
6 x 1.5 = 9.0A; +4A = 13A (choose a 15A power supply)
In this example, it is assumed that all the pumps and other equipment will
sometimes operate simultaneously.
External equipment with inadequate bypass capacitance or that is inadequately
sourced for current can cause overvoltage transients and sags, and can create
unnecessary ripple current in the XLP 6000. This can result in decreased
component life. Additionally, it is possible for a regulated power supply to become
unstable with certain loads and oscillate if adequate filter capacitance is not
present. Some forms of oscillation can cause failures in the XLP 6000. These
issues can be avoided by using a properly designed commercial power supply.
Consideration should also be given to the wiring of the XLP 6000 and any
additional devices. Wiring should be of sufficient gauge for the current, and as
short as possible. Unless otherwise required by safety requirements, the power
supply lines to the XLP 6000 should be 20AWG or heavier. Multiple XLP 6000s
can be daisy-chained, provided that the wire size and the power supply are
adequate for the total current. In the example of the six XLP 6000 pumps above,
use 18AWG wire if the units are daisy-chained. It is best if each pair is twisted or
dressed together from the device to the supply. For more information on multi-
pump cabling, see Section 2.2, Cabling.
To control power to the XLP 6000, switch power to the power supply. Do not use a
relay or switch contacts between the 24V supply and the XLP 6000 (i.e., do not
switch DC input to the pump).
