Production and Calibration of Temp
Production Checklist of STC1000
An analog temperature controller is not very easy to
make. It is used in tough industrial environment and
has to perform with reliability and accuracy on
- Has Transformer been soldered properly with
reinforced pads - Scrape with blade area
around pad and make lead bridges to support
transformer.Front Card and Rear Card must have
very thick solder bridges after fixing sq. post.
- Is the Front and back stickers and SL. No
Sticker properly stuck - In Front Sticker
the holes for switch, pot LED etc. must be
without Burrs file and improve. Acrylic should
not have cynoacralate stains. In the back
sticker there should not be any wrinkles use
rubber solution (fevibond) to stick properly.
- Are all the Threaded parts and Plastic
parts fixed with fevibond - Use Fevibond
(very little) for the CJ box in rear panel all
Metal screws and loose mechanical parts in Pots,
plastic threads and pillars. This prevents parts
from breaking loose during transportation or
vibrations, All Nuts / Bolts fix tightly .
- Are all the Pots. Turning freely and is
direction proper - Clockwise is always
increment or increase in a parameter and
anti-clockwise is decrement of any control or
parameter. All pots should turn without
- Are all the Front panel components Fixed
properly - All Four Displays are required
Fourth is for Overrange and Polarity. LED’s are
for Load On or Process on and Should be neatly
visible above sticker and Switch should not get
stuck after cabinet is closed and screwed.
- Only two screws must be visible on the back
panel - Cover Pot clamp screw, card fixing
screw etc. by Black insulation tape.Use Ni.
plated Phillips / Universal head Screws for
fixing back plate.
- Are all other items in the final packing -
Check by fixing both side clamps and file if
required add Instruction manual in Cover or with
Invoice and DC.
- Sources of omissions and neglect checked by
Visual Inspection - Gnd to Earth
Capacitor to be added 0.01uF 103 1kV,
Polarity of Electrolytic and diodes , Regulator
tab touching any conductor, Loose wire strands,
Solder Bridges absent at places where it is
- Troubleshooting when a card does not work -
Keep always a 3D reference of a working unit
/ card compare component to component by visual
inspection wrong polarity of diodes / Tx / IC,
wrong value of Resistor or Low value capacitors
missing jumpers solder bridges or hairline
shorts at edge of board or pad to pad lead
4-20mA Loop-Powered System
Calibration and Testing Procedure for STC1000P
Power on unit and leave for 15 mts
1-Wire Temperature Control
Calibration Of Room Temperature Preset And Full
Feed 0.00 mV to the TC input using a millivolt
source and adjust P1 (PR1) Z for Display to read
Room temperature as shown by a mercury thermometer.
Feed mV corresponding to maximum temperature and
adjust P2 (FS) for Display to read full scale
temperature. Verify Room temperature again by
feeding 0 mV repeat three iterations till the Zero
and Full-scale readings are set to Room temp (RT)
and FS temp + RT respectively.
e.g. If room temp. is 26 deg. C and as per tables 0
mV is 0 deg C and 16.39 mV is 400 deg C for K type
then feeding 0 mV we should read 26 deg C on TC and
feeding 16.39 mV we read 400 + RT i.e. 426 deg C.
||Reading on TC
|| 0.00 mV
|25 % FS
|50 % FS
|75 % FS
Testing of Proportional Control and Settings.
Adjust Setpoint to Read 300 deg C, Feed mV for unit
to read same PV. Set Proportional Band to MIN fully
anticlockwise till end (100K Ohms).
If Process ON Led in ON turn anticlockwise till it
just turns OFF or flickers. If Process ON Led in OFF
turn clockwise till it just turns ON or flickers.
Now the error cal is calibrated at 300 deg C (for
other temperatures it may differ)
Set Proportional Band to MAX fully clockwise till
end (000 Zero Ohms). (Now SP must be at 300 and PV
must be at 300). Now LED will turn ON for 5 Seconds
(approx.) and OFF for 5 seconds for 10 Sec cycle
time for shorter cycle times just observe
Decrease mV (PV) till LED turns fully ON no
flickering note this Value T1. Increase mV (PV) till
LED turns fully OFF no flickering note this Value
T2. T1 is lower end of PB and T2 upper end T2 - T1 =
PB i. e. the Prop Band .
e.g. T1 = 295 T2 is 305 305 - 295 = 10 hence PB = 10
Verification of Relay operation.
|RESISTANCE “NO” TO “C” in
|GET RELAY TO TURN ON
|GET RELAY TO TURN OFF
Danger ! DMM is in Ohms Mode, Even if one probe
touches 230 V DMM is Gone, so take extra care
while doing this test probe only relay contacts.
For Pulse Output model for SSR e.g. STC1000KPP Use a
DMM 20 V mode to observe 12V DC when Process ON and
0 V when Process off.
Process ON ............. V
Process OFF .............. V
Earth and isolation and safety related
Off Unit before this Test
|GND TO EARTH RESISTANCE
|TRANSFORMER RESISTANCE L to N
|WINDING TO EARTH RESISTANCE L
|CHASSIS TO EARTH RESISTANCE
General Checklist to ensure optimum quality.
- DOES LED TURN ON WHEN RELAY IS ON AND VISE
- DOES DISPLAY READING JUMP WHEN RELAY OPERATES
- SCREWS LOCKED WITH ADHESIVE, POTS TURN SMOOTH.
- ARE ALL STICKERS STUCK PROPERLY WITHOUT FOLDS
- HAVE EXTRA HOLES AND SCREWS COVERED BY B TAPE
- HAS THE SENSOR POLARITY BEEN MARKED WITH PAINT
- HAS THE DB / PB KNOB MARKED BY A WHITE PAINT
Operation of displays and Controls.
Related Documents in PDF Format
- Note SP Min ................ SP max
- Note PB Min ................ PB max
- Feed mV for display to read 1234 Counts
- Feed mV for display to read 345 Counts reading
- Feed mV for display to read -456 Counts
- Feed mV for display to read 1xxx Overrange
- Verify Decimal Point has been connected record
in this > 1 9 9 9
- Display should have uniform brightness without
- Process ON LED must be bright and Visible
- Push-button switch should not get stuck on