CTH Controls Inc.
1.888.550.6829   Supplier Inquiry   About Us      
Eurotherm Action Instrument
Eurotherm Power Control
Eurotherm Power Control
Eurotherm Action Instrument
Eurotherm Chessel
Hardy Process Weight
Hardy Process Weight
London Electronics Ltd.
Paragon Robotics
Ohio Semitronics
Dimetix Inc.
TandD Data Loggers
Ametek Dixson
Precision Digital
Process Sensors Corp
Ultra Electronics
ACTIONI/Q® Q126 AC Powered T/C Input Limit Alarm

Provides Relay Contact Closures at a Preset Temperature Input Level.

  • Field Configurable Input Ranges
  • TouchCALTM Technology
  • Setpoints Programmable HI or LO and Failsafe or Non-Failsafe
  • DIN Rail Mounting with IQRL
  • Universal AC Power 85 to 265 VAC
  • SnapLocTM Plug-in Terminals
  • ASIC Technology

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 offer flexible 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.

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
Action has simplified setpoint calibration. Using a pushbutton instead of potentiometers, improvements in calibration resolu- tion and reliability are realized due to the elimination of the potentiometer's mechanical 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 deadband, 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 green LED is a dual function LED labeled IN, which indicates line power and input signal status. Active AC power is indicated by the illuminated LED. If this LED is off, check AC power and wiring connections. If the input signal is 7% above or below the configured input range the green LED will flash at 8Hz or 4Hz, respectively. The two red LEDs indicate the relay state of each setpoint. An illuminated red LED indicates the tripped condition for the respective setpoint.

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

The Q106 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. The trip will reset only after the process falls below the HI deadband or rises above the low deadband (see Figure 1). For proper deadband operation, the HI setpoint must be set above the LO setpoint. In failsafe operation, the relay is energized when the process is below the HI setpoint or above the LO setpoint (opposite for non- failsafe). In the failsafe mode, a power failure results in an alarm state output.

Dynamic Deadband
Circuitry in the Q106 prevents false trips by repeatedly sampling the input. The input must be 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 results in a "dynamic deadband" -based on time- in addition to the normal deadband.

Unless otherwise specified, the factory presets the Model Q126 as follows:

Type J
  0 to 350 C
  Dual, SPDT
  A: HI, B: LO
  A, B: 0.25%

The AC power input accepts any AC source between 85 and

Note: An I/QRail is required to power the modules. See ordering information.

For other I/O ranges, refer to Table 1 and reconfigure switches
SW1 and SW2 for the desired input type, range and function.

Figure 1: Limit alarm operation and effect of deadband


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

1. With the module removed from the rail and not powered, snap off the faceplate by lifting the right edge away from the heatsink. Note the input switches (SW1 & SW2) are located under the faceplate. Set positions 1 through 3 on "SW1" and positions 1 through 8 on "SW2" for the desired input and range (see Table 1).

2. Set positions 4 and 5 of "SW1" to ON (closed) for a HI trip setpoint or OFF (open) for a LO trip setpoint (Figure 5).

3. Set position 6 of "SW1" to ON for non-failsafe operation or OFF for failsafe operation (e.g., alarm trips upon power failure).

4. Set positions 7 and 8 of "SW1" to upscale or downscale burnout.

1. After configuring the DIP switches, connect the input to a calibrated t/c source and apply power.

Note: For best results, calibration should be performed in the operating environment, mounted on a DIN rail, allowing at least one hour for thermal equilibrium of the system.

2. After applying power to the unit all three LEDs will flash for approximately 10 seconds. Adjust the input signal level for the Relay "A" setpoint. The green LED will be on. Press and hold the CAL button for 4 seconds (until the red LED starts flashing) to enter the calibration mode. The green LED will be on and the red Relay "A" LED will be flashing.

Note: If the green LED is flashing, the input is out of range (i.e. 7% above or below the configured range). Check to make sure the input signal is within the DIP switch configuration range. Double check dip switch settings.

3. Setpoint "A": Input the desired trip level for Relay "A" and push the CAL button. The green and the red Relay "A" LED will be flashing. Note that the green LED will stop flashing when the input drops below a high setpoint or rises above a low setpoint.

4. Deadband "A": For minimum deadband (approximately 0.25%), press and hold the CAL button for 4 seconds. For high setpoints lower the input level to the desired deadband point and push the CAL button. For low setpoints increase the input level to the desired deadband level and push the CAL button. The green LED will be on and the red Relay "B" LED will be flashing.

5. Setpoint "B": Input the desired trip level for Relay "B", and push the CAL button. The green and the red Relay "B" LED will be flashing.

6. Deadband "B": For minimum deadband (approximately 0.25%), press and hold the CAL button for 4 seconds. For high setpoints lower the input level to the desired deadband point and push the CAL button. For low setpoints increase the input level to the desired deadband level and push the CAL button. The green LED will be on and both the red LEDs will be flashing.

7. Press the CAL button once again to exit the calibration mode. Check the setpoint and deadband to validate calibration.

Note: Pressing and holding the CAL button for >8s or no action for more the 2 min will quit the calibration process without saving changes anywhere within the calibration process.

Relay Protection and EMI Suppression
When switching inductive loads, maximum relay life and transient EMI suppression is achieved using external protection (see Figures 2 and 3). Place all protection devices directly across the load and minimize all lead lengths. For AC inductive loads, place a properly- rated MOV across the load in parallel with a series RC snubber. Use a 0.01 to 0.1mF pulse film capacitor (foil polypropylene recom- mended) of sufficient voltage, and a 47 ohm, 1/2W carbon resistor. For DC inductive loads, place a diode across the load (PRV > DC supply, 1N4006 recommended) with (+) to cathode and (-) to anode (the RC snubber is an optional enhancement).

Table 1: Input Range


Figure 2: DC Inductive Loads Figure 3: AC Inductive Loads

Figure 4: Q126 Calibration Flow Chart


Figure 5: Input Range/Function Selection (SW1) Factory Default Settings
Range: See Table 1
Impedance: >1 Megohm
Input Bias Current (burnout detect): <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 Differential (Deadband):
0.25% to 100% of span
Response Time:
Dynamic Deadband:
     Relay status will change when proper setpoint/process condition exists for
Normal Mode (analog filtering):
     <250msec, (10-90%)
Effectivity: Setpoints adjustable over 100% of the selected input span. Repeatability (constant temp.):
     0.2% for temp > 0 C
     0.3% for temp < 0 C
Temperature: 0.05% of full scale/ C, max.
Common Mode Rejection:
DC to 60Hz: 120dB
1800VDC between contacts, input and power
ESD Susceptibility:
Capable of meeting IEC 801-2 level 3 (8kV)
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: -15 to 70 C (5 to 158 F)
2.5W max. 100 to 240VAC 10%, 50 to 400Hz
Relay Contacts:
2 SPDT (2 Form C) Relays, 1 Relay per setpoint
Current Rating (resistive):
     120VAC: 5A; 240VAC: 2A; 28VDC: 5A
Material: Gold flash over Silver alloy
Electrical Life: 105 operations at rated load
Note: External relay contact protection is required for use with inductive loads.
Mechanical Life: 107 operations
Wire Termination:
Screw terminations for 12-22 AWG
Agency Approvals:
UL recognized per standard UL 508 (File No E99775).
CE EN61326, EN61010-1


Ordering Information

Models & Accessories
Specify (model number)
  1. Q126-0000
  2. Specify I/QRail type and quantity (required)
  3. Accessories: (see Accessories)
  4. Optional Custom Factory Calibration: Specify C620 with desired input, setpoint and deadband.
ActionI/Q series 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-2002 2 Position I/QRail & DIN rail IQRL-2004 4 Position I/QRail & DIN rail IQRL-2004 4 Position I/QRail & DIN rail
8 Position I/QRail & DIN rail






Relay A, N.O.


Not Used


Relay A, Common


Not Used


Relay A, N.C.


Thermocouple Input (-)


Relay B, N.O.


Thermocouple Input (+)


Relay B, Common


AC Power (Hot)


Relay B, N.C.


Not Used


Not Used


Not Used


Not Used


AC Power (Neutral)


return to top


CTH Controls Inc.   CTH Controls Inc.
5100 South Service Road, Unit 2
Burlington, ON. L7L 6A5 Canada
Phone: 905-792-6829
Toll Free: 1-888-550-6829
Fax: 905-792-6902
  arrow Products arrow Contact Us  

For Secure Payments
Mastercard Visa
<empty> <empty> <empty>
<empty> <empty> <empty>
  arrow Services arrow Supplier Inquiry  
  arrow Support arrow ISO Certification  
  arrow About Us arrow Return Policy  
    arrow Careers  
  arrow Line Card  
© Copyright 1998-2024, CTH Controls Inc. All rights reserved