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Model TT339-0700
4-Wire Isolated Frequency Transmitter w/USB
Acromag, Inc. Tel: 248-295-0880
[
34
]
http://www.acromag.com
USB Interface
IMPORTANT:
The input of this transmitter is
isolated from its output and can
be connected to grounded or un-
grounded input sensors.
However, the transmitter’s input
circuit ground is connected in
common to the USB
power/signal/shield ground. This
will in-turn make a connection to
earth ground at the PC when
directly connected to the USB
port of a PC without using an
isolator. Failure to connect USB
without isolation would connect
the 1.25V input bias supply to
input ground if the sensor is also
earth grounded. This will
interfere with operation and
cause the output to shift. For
this reason, USB isolation is
strongly recommended when
connecting to a PC. Otherwise, in
the absence of USB isolation,
and when connected to a
grounded input sensor, a battery
powered laptop could be used to
connect to the transmitter, as
the laptop does not normally
connect to earth ground.
Transmitter includes a USB socket for temporary connection to a PC or laptop for the
purpose of setup and reconfiguration. USB isolation is required when connected to a
grounded input sensor (see “IMPORTANT” note on the left). During reconfiguration
and calibration, the transmitter receives power from its power connection (via DIN
rail bus or power terminal), but not USB.
CAUTION:
Do not attempt to connect USB in a hazardous environment. Transmitter
should be configured and calibrated in a safe environment only.
Data Rate:
USB v1.1 full-speed only, at 12Mbps. Up to 32K commands per second.
USB 2.0 compatible.
NOTE:
Transmitter can not service USB interrupts when the input signal frequency is
greater than 124KHz. Input capture interrupts have priority over USB interrupts and
will consequently override USB interrupts at such frequencies.
Transient Protection:
Transient voltage suppression on USB power and data lines.
USB Connector:
5-pin, Mini USB B-type socket, Hirose Electric UX60-MB-5S8.
Pin
Definition
1
+5V Power (Transient protected, but not used by module)
2
Differential Data (+)
3
Differential Data (-)
4
NC – Not Connected
5
1
Power Ground (Connects to Signal Ground via ferrite bead)
SHLD
1
Signal Ground (Connects directly to Signal Ground)
1
Note:
Most Host Personal Computers (except battery powered laptops) will connect
earth ground to the USB shield and signal ground.
Cable Length/Connection Distance:
5.0 meters maximum.
Driver:
No special drivers required. Uses the built-in USB Human Interface Device
(HID) drivers of the Windows Operating System (Windows XP or later versions only).
Power
CAUTION:
Do not exceed 36VDC peak to
avoid damage to the
transmitter. Terminal voltage
at or above 12V minimum
must be maintained across the
transmitter during operation.
Power Supply (Connect at TB4 or via DIN Rail Bus):
12–32VDC SELV (Safety Extra
Low Voltage), 1.3W maximum. Observe proper polarity. Reverse voltage protection is
included. Current draw varies with power voltage as follows (currents indicated
assume a current output is driving 21mA into the load).
Power Supply Voltage
TT339-0700 Current
12V
92mA Typical / 101mA Max
15V
76mA Typical / 84mA Max
24V
44mA Typical / 48mA Max
32V
33mA Typical / 36mA Max
Power Supply Effect:
Less than
±
0.001% of output span effect per volt DC change.
!