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Q448-0000
ACTIONI/Q
®
Q448
DC Powered Bridge Input
Signal Isolator
Provides an Isolated DC Output in Proportion
to a Bridge/Strain Gauge Input
Adjustable Bridge Excitation
Field Configurable Input Ranges
Field Configurable Output Ranges
TouchCAL Technology
Description
The Q448 is a DIN rail mount, DC powered bridge or strain gauge
input signal conditioner with 1800VDC isolation between input,
output and power. Advanced digital technology combined with
ASIC technology allows the Q448 to be field configured for
virtually any Bridge input to DC output within the limits specified.
The input can be set via DIP switches for any one of 11 voltage
ranges from 10mV to ±200mV (see Table 1). The output is linear
to the input and can be set for either 0-5V, 0-10V, 0-1mA or 420mA, direct or reverse acting.
TM
TouchCAL
The Q448 utilizes TouchCAL technology which greatly simplifies
calibration. Once the unit is configured via DIP switches, the
pushbutton is used to precisely calibrate the minimum and
maximum levels. The thermal drift and mechanical variability of
the potentiometers has been removed and replaced with a
digitally stable circuit. Additionally, the inherent zero and span
interactivity of potentiometer based analog amplifier circuitry is
removed, providing 100% non-interactive adjustment.
TouchCAL provides more than 90% offset of the zero value and
adjustment down to 10% of the full scale input span for most of the
11 switch selectable input ranges. For example, the DIP switch
configured 0-100mV input range could be calibrated via
pushbutton for 0-40mV (i.e. 60% span reduction) or offset to a range
of 60-100mV (i.e. 60% offset and 60% span reduction). If the output
was configured for 0-10V, then 60-100mV input would correspond
to the 0-10V full scale output. Thus, an input range such as 90100mV is possible using the 0-100mV range. A TARE function is also
provided to allow batch offsets (0285 and later firmware).
To calibrate the input within the DIP switch configured range,
simply apply the high input signal and push the CAL button. The
low input signal is then applied and pushing the CAL button again
stores the low input signal (these steps are reversed for reverse
mode operation).
The high and low input levels are stored in nonvolatile memory
and correspond to the high and low output levels. These output
levels are precisely adjusted using the input signal.
Technology
High Density DIN Rail Mounting
Flexible DC Power Supply Accepts 18 to 30VDC
SnapLocTM Plug-in Terminals
Diagnostic LEDS
The Q448 has three diagnostic LEDs. The green (RUN) LED is used
for diagnostics to indicate that power is on. It will flash quickly if
the input signal is above the calibrated range or slowly if the input
signal is below range. It is on continuously when the unit is
functioning within the calibrated range.
The yellow (IN) LED is on while calibrating the input and the red
(OUT) LED is on while calibrating the output.
Application
The Q448 bridge input signal conditioner is useful in isolating
ground loops and interfacing bridge sensors to data acquisition and
control systems. Three-way isolation completely eliminates ground
loops from any source. Isolation protects expensive SCADA systems
from ground faults and provides filtering for noise reduction which
can be a significant problem with millivolt bridge signals.
Wide ranging flexibility allows the user to easily zero out deadloads in weighing systems or configure bipolar input ranges for
tension-compression or vacuum-pressure bridge applications.
High density DIN rail mounting offers an extremely compact
solution for saving valuable panel space.
Configuration
The Q448 can be configured for input ranges from 10mV to +/200mV, with 90% input offset, or it will adjust down to 10% of
fullscale input span (except on 10mV, +/-5mV range where
maximum offset or gain adjustment is 50%).
Unless otherwise specified, the factory presets the Model Q448 as
follows:
Input Setting:
Input Range: 0 to 30mV (3mV/V)
Excitation: 10V
Operation: Direct
Output: 4 to 20mA
For other I/O ranges, refer to the tables below.
0 to 50mV
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WARNING: Do not change switch settings with power applied.
Severe damage will result!
1. With power off, snap off the faceplate by lifting the right edge
away from the heat sink. Slide off the metal heatsink.
2. Note that the module has two eight position switch blocks, one
for input and one for output.
3. Choose the desired ranges from Tables 1-4. Return the heatsink
to its original position and attach the faceplate before beginning
calibration.
Calibration
For best results, calibration should be performed in the operating
installation, allowing at least one hour for thermal stability of the
system. If pre-calibration on a test bench is preferred, then an
output load equal to the input impedance of the device connected
to the Q448 output is recommended, along with a 1 hour warm up
period.
1. For best results install the module on to a piece of DIN rail or the
I/Q Rail mounting accessory. See the I/Q Rail data sheet for details.
Note: An I/QRail is required to power the modules. See ordering
information.
2. Connect the input to a calibrated DC source and the output to
a voltage or current meter. Apply power and allow the system to
reach thermal equilibrium (approximately 20 minutes).
3. Adjust the input signal to the desired maximum and observe that
the green LED is on or flashing. Push the CAL button and hold it
down for six flashes of the yellow LED (until the yellow and green
LEDs are flashing), then release the button.
Note: To quit the calibration mode and reset the unit, push the CAL
button again and hold for more than 5 seconds. Or wait for more
than two minutes and the unit will time-out and automatically
reset to the previously stored calibration.
Note: For the reverse operating mode (SW1-6 closed), input the
minimum signal in step 4 of calibration.
4. The yellow and red LEDs will be on. Push the CAL button. Apply
the maximum input signal level desired and push the CAL button
to store. The yellow LED will now be on.
Note: For the reverse operating mode (SW1-6 closed), input the
maximum signal in step 5 of calibration.
5. Apply the minimum input signal level desired and push the CAL
button to store. The green and red LED will now be on.
6. Adjust the input signal while monitoring the output signal until
the output is at the desired maximum level (e.g. 20.00mA), then
push the CAL button to store (the red LED will be on).
7. Adjust the input signal while monitoring the output signal until
the output is at the desired minimum level (e.g. 4.00mA), then push
the CAL button to store (the yellow, green and red LEDs will be on).
8. To finish calibration, push the CAL button once again. The green
LED will be on if the input is within the calibrated range.
Note: The TARE function is enabled by depressing the TARE/(CAL)
until the yellow LED flashes at least once and less than six times. The
input present at that time will be used as the TARE value and the
output will be the minimum output when the module was calibrated.
Table 1: Input Range Settings
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Vm01ot0
Vm02ot0
Vm05ot0
Vm001ot0
Vm002ot0
Vm5ot5-
Vm01ot01-
Vm02ot02-
Vm05ot05-
Vm001ot001-
Vm002ot002-
Table 2: Direct or Reverse Setting
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Table 3: Bridge Excitation Settings
78
V1.01ot8.9
V2.5ot8.4
V01ot0
V5.2ot0
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egatloVegatloV
egatloV
Table 4: Output Range Settings
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V5ot0
V01ot0
Am1ot0
Am02ot4
Am02ot0
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Figure 1: Q448 Calibration Flow Chart
Figure 2: Bridge Reference Designations
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Specifications
r
Input:
Voltage:
Full Scale Range: 10mV to ±200mV (Table 1).
Impedance: >1M ohm
Overvoltage:
Intermittent 400V, max.; Continuous 264V, max.
Common Mode (Input to Ground):
1800VDC, max.
Pushbutton Adjustment:
Effective zero offset: >90%
Effective span turn down: >90% except for 10mV & +/-5mV range
in which 50% is max. zero offset and span turndown
Operation: direct or reverse acting
Output:
Voltage:
Output: 0-5V, 0-10V
Impedance: <10 ohms
Drive: 10mA, max. (1K ohms, min. @ 10V)
Current:
Output: 0-1mA, 0-20mA, 4-20mA
Impedance: >100K ohms
Compliance:
0-1mA; 7.5V, max.(7.5K ohms, max.)
0-20mA; 12V, max. (600 ohms, max.)
4-20mA; 12V, max. (600 ohms, max.)
Bridge Excitation
1 to 10VDC, 120mA max. Current drive decreases at 10mA/V below
5V (e.g. 4V, 110mA max.)
Accuracy
(Including Linearity, Hysteresis):
±0.1% typical, ±0.2% maximum of selected input range at 25°C.
Stability:
±0.025%/°C typical, 0.05%/°C maximum, of selected full scale input range.
Output Noise (maximum):
0.1% of span, rms, or 10mV, whichever is greater.
Response Time (10 to 90%):
<200mSec., typical.
Ordering Information
Models & Accessories
Specify:
1. Model: Q448-0000;
2. Specify optional I/QRail, type and quantity.
3. Optional Factory Custom Calibration, specify C620 - with desired
input and output ranges.
4. Accessories: (see Accessories)
Common Mode Rejection:
DC to 60Hz: 120dB, 100dB (0 -1mA, range)
Isolation:
800VDC between input, output and power.
LED Indication (green):
Input Range (approx.)
>110% input: 8Hz flash
<0% input: 4Hz flash
Humidity (Non-Condensing):
Operating: 15 to 95% @ 45°C
Soak: 90% for 24 hours @ 65°C
Temperature Range:
Operating: 0 to 55°C (32 to 131°F)
Storage: -25 to 70°C (-13 to 158°F)
Power:
Consumption:
2.7W typical (one 350 ohm bridge)
4W max. (four 350 ohm bridges).
Range: 18 to 30VDC
Shipping Weight:
0.54 lbs.
Wire Terminations:
Screw terminals for 12-22 AWG
Agency Approvals:
UL recognized per standard UL508 (File No. E99775).
CSA certified per standard C22.2 No. 0-M91 and 142-M1987
(File No. LR42272-84).
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Dimensions
Accessories
ActionI/Q modules mount on standard TS32 (model MD02) or TS35 (model
MD03) DIN rail. In addition the following accessories are available:
MD02 TS32 DIN rail
MD03 TS35 x 7.5 DIN rail
IQRL-D002 2 Position I/QRail & DIN rail
IQRL-D004 4 Position I/QRail & DIN rail
IQRL-D008 8 Position I/QRail & DIN rail
WV905 24VDC Power Supply (0.5Amp)
H910 24VDC Power Supply (1Amp)
H915 24VDC Power Supply (2.3Amp)
Printed on recycled pape
Action Instruments
Chessell
Eurotherm
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