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K8AC-H

4

Specifications

Ratings

*1.

The gate input enables correct measurement by syncing to heater control. 

When using it with ON/OFF control, receive the relay contact output from the temperature controller or other controller with a 24-VDC auxiliary 

relay and then use this signal as the gate input signal to the K8AC. 

The gate function can also be disabled. If it is disabled, the gate input can be used as a normal undercurrent/overcurrent relay. 

*2.

When using the K8AC-H for a 380 to 480-V AC power supply circuit, use a step-down transformer. Contact your OMRON representative for 

information on transformers.

*3.

Order the Current Transformers separately.

Heater control method

Models for ON/OFF control (e.g., SSRs or contactors)

Models for phase control and cyclic control

Item

Model

K8AC-H

@@

C

@

-FLK

K8AC-H

@@

P

@

-FLK

Power supply voltage

100 to 240 VAC (50/60 Hz) 

*

2

Operating voltage range

85% to 110% min. of the rated power supply voltage (85 to 264 V)

Power consumption 
(at max. load) 

35 VA max.

Applicable circuits

Single-phase or three-phase (with same model)

Applicable control methods

ON/OFF control (e.g., temperature controller with relay output) 

SSR control (e.g., temperature controller with voltage output) 

Cyclic control and phase control (e.g., temperature controller with current output)

Input signal and applicable Current 
Transformer

Current measurement via two special Current Transformers (Burnout alarm set value can be set separately for each Current 

Transformer.)

Refer to 

Current Measurement Ranges by Model

 on page 6 for information on the current measurement range and 

applicable Current Transformer.

Measurement method

Average value calculation

Gate input 
signal 

*

1

ON/OFF control

Voltage = 12/24 VDC (continuous input possible to 30 VDC) 

Input impedance = 4 k

Ω

 min. 

---

SSR control

ON voltage: 9.6 VDC max., OFF voltage: 1 VDC min. 

Minimum voltage pulse ON time for burnout detection: 

200 ms min.

Input impedance = 4 k

Ω

 min. 

---

Cyclic and phase con-
trol

---

4 to 20 mA DC (Burnout detection is possible for an input of 

7 mA or greater.)

Input impedance = 50 

Ω

 max.

Outputs

Relay contact outputs:
K8AC-H

@@@

C-FLK

One SPDT relay contact output

Same output used for heater burnout, SSR short circuit, SSR open circuit, and heater layer short circuit alarms. 

0.3 A at 125 VAC (resistive load), 1 A at 30 VDC (resistive load)

Maximum switching capacity: 37.5 VA, 30 W

Mechanical durability: 50 million operations min., electrical durability: 100,000 operations min.

Transistor outputs 
(NPN open-collector):
K8AC-H1

@@

T-FLK

Two transistor outputs (NPN open-collector)

One ALM output: Outputs heater burnout alarm or heater layer short circuit alarm.

One SSR error output: Outputs SSR short circuit alarm or SSR open circuit alarm.

12 to 24 VDC, 50 mA max.

OFF leakage current: 100 

μ

A max., ON residual voltage: 1.5 V max.

Transistor outputs:
K8AC-H2

@@

N-FLK

Two transistor outputs: Can be used either NPN open-collector outputs or PNP equivalent outputs.

One ALM output: Outputs heater burnout alarm or heater layer short circuit alarm.

One SSR error output: Outputs SSR short circuit or SSR open circuit detection.

12 to 24 VDC, 50 mA

OFF leakage current: 100 

μ

A max., ON residual voltage: 1.5 V max. 

Communications

RS-485   1200, 2400, 4800, 9600, 19200 bps (CompoWay/F)

Indication method

7-segment digital display: No. of display digits: 4 (red)

LED status indicators: RUN (green), ADJ (orange), SET (orange), GATE (orange), SSR (orange) and ALM (orange) 

Main functions

Heater burnout alarm, heater layer short circuit alarm, SSR short circuit detection, SSR open circuit detection, voltage 

fluctuation compensation, output ON-delay timer, energy-saving mode, key protection, and power supply voltage 

measurement

Ambient
temperature

Operating

10 to 55

°

C (with no icing or condensation)

Storage

25 to 65

°

C (with no icing or condensation)

Ambient
humidity

Operating

25% to 85% (with no condensation)

Storage

25% to 85% (with no condensation)

Altitude 

2,000 m max.

Accessories

Instruction sheet

Case material

PC (Polycarbonate)

Case color

N1.5 (clear black)

Mounting method

Mounting to a DIN Track

Summary of Contents for K8AC-H Series

Page 1: ...nitor 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...

Page 2: ...re linked with the control output value from the temperature controller Compatible with Gradient Settings of Power Controllers When using gradient settings with a power controller set a gate current l...

Page 3: ...tput specifi cations Com munica tions output Current input range 0 200 to 2 200 A 2 00 to 22 00 A 20 0 to 200 0 A 100 to 240 VAC ON OFF control SSR control Two current inputs for either single phase o...

Page 4: ...ut impedance 4 k min Cyclic and phase con trol 4 to 20 mA DC Burnout detection is possible for an input of 7 mA or greater Input impedance 50 max Outputs Relay contact outputs K8AC H C FLK One SPDT re...

Page 5: ...als and output terminals Dielectric strength 2 000 V for 1 min Between terminals and case Between power supply terminals CT primary terminals and gate input terminals communications terminals Between...

Page 6: ...VAC 0 3 A 30 VDC 1 A Maximum contact voltage 125 VAC 60 VDC Maximum contact current 1 A Maximum switching capaci ty 37 5 VA 30 W Minimum applicable load failure rate P value refer ence value 5 VDC 10...

Page 7: ...ct to the operating power supply All models 3 to 4 5 to 6 Outputs Outputs SSR open or short circuit detection results Outputs heater burnout or layer short circuit detection results K8AC H2 N transist...

Page 8: ...CTs for three phase heaters For three phase heaters always set the burnout alarm set values for both CT1 and CT2 5 6 3 4 Transistor Output K8AC H2 N FLK CT2 CT1 3 7 8 9 10 11 12 13 14 1 2 RS 485 X 4 5...

Page 9: ...ransistor Output K8AC H2 N FLK Heater Power supply Power Regulator Temperature Controller 4 to 20 mA current output Operation Description If the heater current detected at either CT1 or CT2 falls belo...

Page 10: ...o after one heater burns out with the current prior to the burnout i e the normal current taken as 1 3 In actual operation there may be effects from factors such as load heater imbalances so conduct a...

Page 11: ...s output accordingly SSR Short Circuit Detection If current is measured when there is no gate input an SSR short circuit error is detected and an alarm is output SSR Open Circuit Detection If current...

Page 12: ...Short Open Circuit Alarm Using the Power Regulator s Gradient Settings The power regulator s gradient settings can be used to prevent malfunction by setting the operation gate current level The relati...

Page 13: ...or over OFF for less than 4 mA SSR SSR error Lights when an SSR error occurs open or short circuit OFF when SSR is normal ALM Alarm Lights for heater burnout or overcurrent OFF at all other times Up k...

Page 14: ...pe P should be selected Type P is also selected for cyclic control Select the appropriate relay or transistor output specifications depending on the application K8AC H Parameter Settings Procedure Onl...

Page 15: ...freshed each time an alarm is output and it is saved in non volatile memory The value is saved when power is interrupted The number of outputs is not counted for the test function After counting to 99...

Page 16: ...r at least 1s Press the L key for at least 1 s Press the S key for at least 1 s Press the L key for at least 1s When the key is released Press the S key for at least 1 s Press the L and M keys Press t...

Page 17: ...layer short circuit detection function SSR open circuit detection function SSR short circuit detection function Output ON delay time Soft startup time Startup lock time Gate input function Alarm hyst...

Page 18: ...99 9 s 0 0 OFF SSR Short Circuit Detection Turns the SSR short circuit detection function ON and OFF ssht ON OFF OFF SSR Open Circuit Detection Turns the SSR open circuit detection function ON and OFF...

Page 19: ...te current level Sets the gate current level for SSR operation This setting is valid only when cyclic or phase control is selected as the heater control method sglv 4 0 to 20 mA 7 0 mA Cycle time 3 Se...

Page 20: ...ntact Approx 3 dia 18 22 Approx 6 dia Plug Contact Lead Plug 100 15 30 30 5 Two M3 Depth 4 max 12 dia 40 40 5 15 Current Transformer K8AC CT200 Pre wired Leads Current Transformer K8AC CT200L 1 8 76 4...

Page 21: ...o can cause unintended operation and may result in accident or corruption of the product 3 Do not use thinner or similar solvent for cleaning Use commercial alcohol 4 When discarding properly dispose...

Page 22: ...larm of the K8AC H P FLK when phase control is used Set the burnout alarm value of the K8AC H P FLK based on the current measurement value with the heater output at 100 This is because the burnout det...

Page 23: ...RODUCTS UNLESS OMRON S ANALYSIS CONFIRMS THAT THE PRODUCTS WERE PROPERLY HANDLED STORED INSTALLED AND MAINTAINED AND NOT SUBJECT TO CONTAMINATION ABUSE MISUSE OR INAPPROPRIATE MODIFICATION OR REPAIR A...

Page 24: ...em as a whole has been designed to address the risks and that the OMRON products are properly rated and installed for the intended use within the overall equipment or system Authorized Distributor In...

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