Carel pCO

11
THE UNIT DOES NOT START
LED of the ON/OFF button is turned OFF, the display is OFF, other LEDs
turned OFF.
Check :
a. that power supply is present
b. that there are 24 VAC of power supply voltage at the secondary coil
transformer (220 - 24 VAC)
c. the correct insertion of 24 VAC power supply connector in the proper socket.
WHEN TURNING ON THE INSTRUMENT YOU FIND:
alarm LED indicator ON ,
display with no or random messages
buzzer ON.
Check :
a. that the Eprom has been inserted with the correct polarity
b. that the Eprom pins have not been bent on inserting the Eprom itself
c. that the microprocessor chip has not been damaged: in that case contact the
assistance.
WRONG INPUT SIGNALS READING
Check:
a. that the connection of probes cables is in accordance with instructions
b. that probe signals pass on cables installed at a sufficient distance from
possible excessively disturbing sources (power cables, contactors, high-
voltage cables and cables with high inrush ampere consumption connected
devices)
c. connections between interfaces and controller (flat cables)
d. correct power supply of interfaces and probes
DAMAGED EPROM ALARM
a. Contact the assistance
THE CONTROLLER ACTIVATES THE WATCH-DOG FUNCTION, THAT IS IT TURNS ON
AND OFF AS FOR A POWER SUPPLY FAILURE OR ACTIVATES SOME OUTPUTS AT
RANDOM (DIGITAL AND/OR ANALOGUE)
Check :
a. the connections between controller and interfaces
b. that power cables do not pass near interfaces and control board
microprocessors.
- DIGITAL VOLTAGE INPUTS CONNECTION (220 Volt ac; 24 Volt ac)
The pCO controller allows voltage digital inputs to be connected with terminals ID11 -
ID11R and ID12 - ID12R as shown in the picture below.
When the general alarm input is open, the high pressure alarm on pCO input will be
detected.
Connections must be done as follows:
Digital Input 11 : connection between
ID11R
(common) and
ID11 (24V)
if 24V are
applied, or between
ID11R
(common) and
ID11 (220V)
if 220V are applied.
Digital Input 12 : connection between
ID12R
(common) and
ID12 (24V)
if 24V are
applied, or between
ID12R
(common) and
ID12 (220V)
if 220V are applied.
N.B.
Do not apply 220V to the terminals ID11 (24V) and ID12 (24V).