Proportional Process Controller Specifications
Front Panel Controls
Unlike a On Off temperature controller that works
like a Thermostat. A Proportional controller turns
on for a duration proportional to the heating
required to ramp up the process.
Thermostat
with digital display for PTC1000
If the set value and process value have a large
difference the On period may be 90%. When the
process value is close to set value, the on period
is like 10%.
The on off cycle time is 10 seconds for
electromagnetic relays. it could be 1 second for
SSR. It could reduce further for mosfet switching.
This is similar to PWM.
Display - Process Value PV
This is a 3 1/2 digit display which shows the
process value from 000 to 1999 as chosen by user it
could be deg C, Kg/cm2 or Lts/hr.
Push Switch - Displays Setpoint
This is a push switch which when pressed, makes
Display read SetPoint as required by user to
control his process.
On-Output Status
LED Indicates Relay ON or OFF in Relay and Pulse
Output Units. Units with 0-10V or 4-20mA, Output
LED is always OFF.
Vary SetPoint SP
This is an endless 10 Turn Potentiometer this is
used to adjust SetPoint (SP) in tandem with Push
Switch. Turning Clockwise it Increments SP till max.
value, then turn anticlockwise to bring SP to Zero.
Use a Plastic Screwdriver or Trimmer.(Tester).
Basic Operation
Press Push Switch to make Display read SetPoint
(SP), this is the user defined point at which
process is controlled. Now holding Push Switch
pressed, adjust SP Pot to change Set Point to
required value, use a small screwdriver.
Back Panel Terminations
INPUT : 4 to 20 mA, Fused, Polarity is Important.
From Sensor, DC Current.
OUTPUT : 4 to 20 mA, Polarity is Important. To
Output Device or Actuator, which by using DC
Current, drives 0% 4mA, 50% 12mA and 100% 20mA in
Linear fashion.
SUPPLY : 230V 50Hz - L, N, E. Connect Proper Earth.
BAND : This is a Single Turn Potentiometer (300 deg)
it sets the
Proportional Band of Control. Wide and Narrow are
the ends of pot.
RESET : This is a Ten Turn Potentiometer (endless)
it sets the
Integral or Reset or Error Cal. Inc. PV
and Dec. PV are the two ends of pot.
Electrical Precautions -
- Wrong Connections are the cause of most
equipment failure.
- Use Servo stabilizer for extra protection.
- Use a Very good earth connection.
- Use Fuses where appropriate.
- Crimp and Solder all Lugs.
Specifications
OUTPUT :
- 4 to 20mA, 4mA 0% & 20mA 100%. < 4mA
OFF, > 20mA ON.
- 4-20mA Maximum Voltage @12V DC ie Shunt 10
Ohms to 500 Ohms.
- Protection - use external fuse of 0.1A to
safeguard from high energy circuits.
INPUT :
4 to 20mA, 4mA Displays 0% of Process Value ‘000’
& 20mA Displays 100% of Process Value. This is
to be specified by user as ... an example 750
Lts/hr.
Input @ 20 Ohms Shunt in STC1000PFC. Protection -
Internal fuse of 2A and Semiconductor Protection
Circuits to
safeguard from high energy circuits.
Environmental Limitations :
- Delicate Precision Instrument
- Maximum 50 Deg C, 70% RH Non-Condensing
- Acid-Alkali-Salt Free area.
- Equipment may fail if environment is Hot /
Corrosive / Vibrating.
Cleaning and Maintenance : No Maintenance required,
Clean front panel with moist sponge & Mild
Detergent.
Power Supply : 230V AC 50Hz +/- 10%, Sine wave UPS
& DG Sets.
Feedback
and Temperature Control
Proportional Temperature Controller
A Temperature controller made with above process
controller has the following changes in specs.
On-Output Status
LED Indicates SSR ON or OFF. Pulse Output goes High
Max 15V or Low 0V. High Pulse turns on SSR. and this
is Indicated by LED turning ON.
Display - Process Value PV
This is a 3 1/2 digit display which shows the
Temperature value in Deg. Centigrade
Terminations
INPUT : Thermocouple, Polarity is Important.
OUTPUT : DC Pulse Polarity is Important. To SSR.
Pulse Maximum Voltage 12V DC at a Load of 250 Ohms.
Read More here - Analog
Process
Control Circuits
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