Model DT233-0600
Dual Two-Wire mV/TC Input Transmitters
Acromag, Inc. Tel: 248-295-0880
- 30 -
http://www.acromag.com
- 30 -
https://www.acromag.com
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
loop and that your loop power
supply voltages are sufficient to
supply over-scale current into the
loads (MIN 0.020*Rload), plus 7V
MIN at the unit terminals, plus any
line drop.
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
Software Does Not Detect Unit or Communication Set up
Screen is Blank…
USB is not connected between
unit and host PC.
Verify USB cable from USB isolator is plugged
into the unit and the isolator. Verify that USB
cable from PC is also plugged into the PC USB
port and into the isolator.
USB has not enumerated the
device.
Use the reset button on the Acromag USB
isolator to trigger renumeration of the
transmitter, or simply unplug and re-plug the
USB cable to the transmitter.
Communication or power was
interrupted with USB
connected and config software
running.
Close the current connection with the
software, then select and re-open the
transmitter for communication (or simply exit
the Configuration software and reboot it).
Cannot Communicate with Transmitter
via USB…
Unit fails to operate or exhibits an output shift…
Output shifts off-
range when you connect USB…
A missing USB Isolator could
cause a ground loop between a
grounded input signal/sensor
and earth ground at the
connected Personal
Computer’s USB port.
Isolated splitters and transmitters can be
used with grounded or ungrounded inputs,
but you can only connect grounded sensors if
the USB signals are also isolated. Without
USB isolation, a ground loop is created
between a grounded input and earth ground
of the PC USB port. Th
is module’s
input is
biased 1.25V off input ground to allow it to
process negative-going signals. Earth ground
applied via the non-isolated USB connection
with an earth grounded sensor would clip the
input bias and truncate the negative signal
range. It is best to connect to USB via a USB
isolator for this reason and for increased
safety and noise immunity. 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.
Output is Erratic, not
operational, or at Wrong Value…
Is your output loop power
supply at the correct level for
your load?
Is Output Fault LED blinking?
Verify loop voltage and level in each output.
Ideally, your supplies must be adequate to
provide 7V MIN to the transmitter, plus the
IR drop in the load, plus the IR drop in the
lead wires, and all at the maximum loop
current (>20mA).
