KTA-269 SSR Duty Controller
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Controls an SSR duty ratio with configurable
PWM frequency
4 to 20 mA, 0 to 20 mA, 0 to 5 V or 0 to 10 V
Analog input
5 V output pulse
DIN rail mount option
Description
The KTA-269 is a small current or voltage to PWM duty cycle converter. It has been designed to drive
solid state relays (SSRs) to switch loads such as heaters or lighting.
The PWM frequency is configurable using DIP switches on the board and the PWM duty cycle (on time to
off time ratio) is controlled by an analog input.
The controller accepts 4 to 20 mA, 0 to 20 mA, 0 to 5 V or 0 to 10 V analog input signals. It can be
powered from 8 to 30 VDC. The controller comes in two versions: a bare PCB card and a DIN-rail
mountable version.
Connections
All connections are made to the unit via screw terminals.
Name
Vs
5V
GND
0-5V
0-10V
0-20mA
GND
OUT
FB
16 Mar 2016
Description
Power supply positive connection
5V output for potentiometer
Power Supply Negative Connection
0 to 5 VDC analog input
0 to 10 VDC analog input
0 to 20 mA or 4 to 20 mA analog input
Power supply negative connection
Output positive connection
Not used in the KTA-269
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KTA-269 SSR Duty Controller
Example input wiring configurations are shown below:
Configuration
The board has 8 small DIP switches. The switches can be moved using a small flat bladed screw driver or
ballpoint pen. Switches 1, 2, and 3 are unused. Switches 4, 5, and 6 set the PWM frequency. Switches 7
and 8 set the ADC Input.
The input signal is selected with the switch settings shown below.
SW7
OFF
OFF
ON
ON
SW8
OFF
ON
OFF
ON
ADC Inputs
0 to 20 mA
4 to 20 mA
0 to 5 V
0 to 10 V
The SSR switching frequency is set by switches SW5, SW4 and SW3 as per the table below. In general
SSRs will endure more heating at high frequencies. Higher frequencies result in smoother output – for
example, in lighting applications frequencies below 60 Hz will cause visible flicker. AC switching SSRs
often only switch at the line zero crossing – limiting their operation to less than 100 Hz. Consult your SSR
datasheet for limits to switching time or frequency.
SW3
OFF
OFF
OFF
OFF
ON
ON
SW4
OFF
OFF
ON
ON
OFF
OFF
SW5
OFF
ON
OFF
ON
OFF
ON
Frequency
0.0625 Hz
0.9537 Hz
62.5 Hz
488.28 Hz
7.8125 kHz
16 kHz
Period
16 s
1.0486 s
16 ms
2.048 ms
128 μs
62.5 μ
Model Selection
KTA – 269
SSR Duty Controller
A: PCB
D: Din Rail Mount
16 Mar 2016
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