The ActionI/Q model Q126 is a DIN rail mount, thermocouple input limit alarm with input terminal cold junction compensation (cjc), dual setpoints and two contact closure outputs. The field configurable input and alarm functions offerflexible setpoint capability. There are up to six temperature ranges available for each thermocouple type to ensure accuracy and maximize setpoint resolution. A bipolar input switch is provided for temperature ranges below 0°C.  

Thanks to Action's exclusive TouchCAL Technology, the Q126 is configurable as a single or dual setpoint alarm, with HI or LO trips, upscale or downscale thermocouple burnout detection and failsafe or non-failsafe operation. Also included are adjustable deadbands (up to 100% of full scale input) for each setpoint and a universal AC power supply which accepts any voltage between 85 and 265VAC.

Touchcal Technology

Advances in microprocessor technology enable Action to simplify setpoint calibration. Using a push- button instead of potentiometers, improvements in calibration resolution and reliability are realized due to the elimination of the potentiometer's variability.

For calibration, the user simply inputs the signal level of the desired trip, then presses the push-button to store it in non-volatile memory. The dead band, or hysteresis, level is input next and is stored with another press of the button.

Diagnostic LEDs

The Q126 is equipped with three front panel LEDs. The first is a dual function LED labeled IN (INPUT) This green LED indicates AC power and input signal status. Active AC power is indicated by an Protecting the Integrity of Industrial Process Signals An Invensys Company illuminated LED. If this LED is off, check line power and wiring connection. If the input signal is 7% above or below the configured input range the green LED will flash at 8Hz or 4Hz, repectively.

Two red LEDs indicate the relay state for each setpoint. An illuminated red LED indicates a tripped condition.

Output

The Q126 is equipped with two SPDT (form C) relays, rated at 120VAC or 28VDC at 5 amperes. Each of these relays is independently controlled by the field configurable setpoint and deadband. 

Operation

The field configurable Q126 limit alarm setpoints can be configured for HI or LO, failsafe or non-failsafe operation. Each of the setpoints has a respective HI or LO deadband. In a tripped condition, the setpoint is exceeded and the appropriate red LED will illuminate.

Dynamic Deadband

LSI circuitry in the Q126 prevents false trips by repeatedly sampling the input. The input must remain beyond the setpoint for 100 milliseconds, uninterrupted, to qualify as a valid trip condition. Likewise, the input must fall outside the deadband and remain there for 100 milliseconds to return the alarm to an untripped condition. This effectively results in a “dynamic deadband” —based on time— in addition to the normal deadband.

Inputs 

• Range: See Table 1

• Impedance: >1 Megohm

Input Bias

• Current (burnout detection): <1.5 microamp

• Overvoltage: ±10V differential

• Common Mode (Input to Ground):   1800VDC, max.

LED Indicators 

• Input Range (Green)    

• >110% input: 8Hz flash

• <-10% input: 4Hz flash

Setpoint (Red): 

• Tripped: Solid red

• Safe:off

Limit Differentials (Deadbands)   

0.25% to 100% of span

Response Time 

• Dynamic Deadband: Relay status will change when proper setpoint/process condition exists for 100msec

• Normal Mode (analog filtering): <250msec, (10-90%)

Setpoint 

• Effectivity: Setpoint(s) are adjustable over 100% of the selected input span

• Repeatability (constant temp.): 

  • 0.2% for temp > 0°C

  • 0.3% for temp < 0°C

Stability     

Temperature: ±0.05% of full scale/°C, max.

CMRR     

DC to 60Hz: 120dB

Isolation   

1800VDC between contacts, input and power