Digital Heater Element Burnout Detector K8AC-H A high-precision Heater Element Burnout Detector compatible with a wide-range of heater control methods. Push-in terminals reduce the workload. Scaling NPN or PNP equivalent output. Lineup includes models compatible with many heater control methods, including ON/OFF control, phase control, and cyclic control. High-precision heater burnout alarm with digital measurement. Contributes to preventative maintenance. If the gate function is disabled, the gate input can be used as an undercurrent/overcurrent relay or for motor or lamp loads. Undercurrent detection values can be set separately for CT1 and CT2. * CE marking and cUL certified. * The overvoltage detection value is the same for the CT1 and CT2. Also, there is one undercurrent output. Wide Current Input Range: 0.200 to 200.0 A AC. Note: 1. Consult with your OMRON representative before using the K8AC with phase control or cyclic control under the following conditions. Using multiple heaters with different heater capacities For the most recent information on models that have been certified for Using heaters with varying heater resistance (e.g., halogen heaters) safety standards, refer to your OMRON website. 2. The K8AC-H is designed to monitor for element burnouts on heaters controlled with power regulators that used a three-alarm method. Normal monitoring is not possible for circuits that use a power regulator with a six-alarm method. Features High-precision Heater Burnout Alarms with Push-in Terminals for Reduced Wiring Work Push-in terminals have no screws to come loose, which eliminates High-resolution Digital Measurement the need to control screw tightening torque and retighten screws and Burnout Alarm Possible for One of Multiple helps to reduce your workload. Heater Elements Heater burnout is detected by digitally processing minor current fluctuations. RST E5 Digital Temperature G3PE Controller Easily connect terminals using ferrules with insulation sleeves. Three-phase SSR Easy Scaling Using the External CT Ratio and Number of CT Passes Easily set the scaling just by inputting (1) the CT ratio and (2) the number of CT passes. Current Transformer External CT K8AC-H Digital Heater A/1A Element Burnout Detector (1) CT ratio K8AC-CT Current Transformer Electric oven (2) Number of CT passes Three-phase Heater delta-connected heater 1K8AC-H Compatible with Various Heater Control The transistor output from the K8AC-H2 N Methods can be used as either an NPN open-collector output or a PNP equivalent output. Models with heater burnout alarms for ON/OFF control, phase control, and cyclic control have been added to the lineup. The transistor output of the K8AC-H2 N uses a photocoupler for Check the current input range, connected CT, and relay output type isolation with the internal circuits, and so either an NPN open- before selecting the model from the product specifications. collector output or a PNP equivalent output can be used. Note: Both single-phase and three-phase heaters are supported. NPN Output PNP Equivalent Output Overcurrent and SSR Failure Detection from Heater Layer Short Circuits. Overcurrent can be detected from layer short circuits in addition to providing heater burnout alarms with overcurrent detection Load Load settings. SSR short circuit failures and SSR open circuit failures are Load power supply detected by monitoring the heater current and the control outputs Load power supply from the temperature controller. Detecting SSR failures enables promptly discovering that Preventive Maintenance temperature control has failed. The run time can be measured by the K8AC-H. Managing the run time history until burnouts occur is useful for Heater Burnout Alarms for Cyclic Control or diagnosis and preventative maintenance for equipment. Phase Control Heaters Count the Total Number of Alarms Output (K8AC-H P ) Set the upper and lower limits to count the total number of alarms that The burnout detection value is shifted according to the have been output. control output value from the temperature controller. Analog control is performed on the output power according to the temperature controller s current output (4 to 20 mA) when phase control or cyclic control is used. Heater burnout alarms are stable with the K8AC-H because the heater burnout alarm values are linked with the control output value from the temperature controller. Heater current Heater Burnout Alarm Value The heater burnout alarm value shifts according to the control input (4 to 20 mA) from the temperature controller. Heater burnout alarm value 4 mA 7 mA 20 mA Control output from temperature controller Compatible with Gradient Settings of Power Controllers When using gradient settings with a power controller, set a gate current level that is suitable for the gradient settings. Output current 100% Gradient setting: 100% Measurement range Gradient setting: 50% 0% Control signal 4 mA 14 mA 20 mA Not detected Detected Operation gate current level Note: Set the heater burnout alarm value based on the current at the heater s rated input. 2 Heater current