Touchcal Technology
The Q448 utilizes Action Instruments’ TouchCAL technology which greatly simplifies calibration. Once the unit is configured via DIP switches, the push-button is used to precisely calibrate the minimum and maximum levels.

To calibrate the input within the DIP switch configured range, the user simply applies the high input signal and pushes the CAL button. The low input signal is then applied and pushing the CAL button again stores the low input signal. Note, 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.

Diagnostic LEDs
The Q448 has three diagnostic LEDs. One green LED, labeled RUN, is used for diagnostics to indicate that power is on, and it will flash quickly if the input signal is above the configured range or slowly if the input signal is below range. The RUN LED is continuously on when the unit is functioning within the configured range.

The yellow IN LED is on while calibrating the input and the red OUT LED is on while calibrating the output.

This flexibility, combined with an adjustable (1 to 10VDC) bridge excitation source, provides the user a reliable, accurate instrument to isolate and condition virtually any bridge or strain-gage input.

Application
The ActionI/Q Q448 field configurable, 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 small, millivolt, bridge signals.

Wide ranging flexibility allows the user to easily zero out dead-loads in weighing systems or configure bipolar input ranges for expansion-compression or vacuum-pressure bridge applications.

High density DIN rail mounting offers an extremely compact solution for saving valuable panel space.

Configuration
A major advantage of the Q448 is its wide ranging capabilities and ease of 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:

The DC power input accepts any DC source between 18 and 30V, typically a 24VDC source is used (see Accessories).

WARNING: Do not attempt to change any switch settings with power applied. Severe damage will result!

Regarding other I/O ranges, refer to Table 1 for input range (SW1) switch settings, Table 2 for input direction settings, Table 3 for excitation level and Table 4 for output ranges (SW2). For quick and easy calibration mode reference, see the step-by-step flow chart in Figure 1.

1. With power off, snap off the face plate by lifting the right edge, away from the heat sink. Then, slide the heat sink forward and off the module.
2. Note, the module has two eight position switch blocks, one for input and one for output.
3. Change Dip switches for desired ranges using Tables 1-4. Attach heatsink and face plate before begining calibration.