Acromag, Inc. Tel: 248-295-0880
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Model SP33X-0700
4-Wire DC I/V Signal Splitter w/USB
TROUBLESHOOTING
Diagnostics Table
Before attempting repair or
replacement, be sure that all
installation and configuration
procedures have been followed
and that the unit is wired properly.
Verify that power is applied to the
unit and that your supply voltage is
at least 7V. Verify that your load is
appropriate to your output type,
current or voltage
If your problem still exists after
checking your wiring and reviewing
this information, or if other
evidence points to another
problem with the unit, an effective
and convenient fault diagnosis
method is to exchange the
questionable unit with a known
good unit.
Acromag’s Application Engineers
can provide further technical
assistance if required. Repair
services are also available from
Acromag.
POSSIBLE CAUSE
POSSIBLE FIX
Cannot Communicate with Unit via USB…
Output shifts off-
range when you connect USB…
Output Erratic, Not opera
tional, or at Wrong Value…
Unit fails to operate or exhibits an output shift…
A missing USB Isolator could
cause a ground loop between a
grounded input sensor and
earth ground at the connected
Personal Computer’s USB port.
Without USB isolation, a ground loop is
possible between a grounded input and earth
ground of the PC USB port. The input to this
model is normally biased up 1.25V off input
ground to process negative-going signals. A
grounded signal source could inadvertently
short this bias to earth ground and clip the
negative input range with a non-isolated USB
connection. For this reason and for increased
safety and noise immunity, it is best to
connect to USB via a USB isolator. Use an
isolator like the Acromag USB-ISOLATOR.
Otherwise, use a battery powered laptop to
configure the transmitter, which does not
normally earth ground its USB port.
Software Fails to Detect Transmitter…
Bad USB Connection
Recheck USB Cable Connection.
(Agility) Your smart device
needs permission to connect to
the Acromag splitter the first
time.
When you first connect to your smart device,
it will prompt for permission. Be sure to give
your permission or Agility will not discern
your device connection. You may have to
unplug/replug the USB connection to your
tablet/phone to get this prompt.
USB has not enumerated the
device.
Use the reset button on the Acromag USB
isolator to trigger renumeration of the unit,
or simply unplug and re-plug the USB cable to
the splitter.
Communication or power was
interrupted while USB was
connected and configuration
software running.
Close the current connection with the
software, then select and re-open the splitter
for communication (or simply exit the
Configuration software and reboot it).
For an input step, the output appears to make
2 steps to reach its final value…
For a step change in the input,
the A/D needs 2 input samples
to charge to its final level.
When you step the input, it takes two
samples for the A/D to charge to its final
output level, evident when using a scope to
examine the output transition in response to
an input step change, which appears to make
two steps in its transition to its final level.