Carel pCO1 series User Manual

pCO Sistema
Code: +030220336 - rel. 1.5 - 22/12/10
62
9. TROUBLESHOOTING
 The unit does not start (power LED off)
The unit does not start (power LED off)The unit does not start (power LED off)
The unit does not start (power LED off)
Check:
1. the mains power supply;
2. that 24 Vac/Vdc is available downstream of the power transformer;
3. that the 24 Vac/Vdc power connecter is plugged in correctly;
4. that the protection fuse is intact (if featured);
 On power
On powerOn power
On power-
--
-up or during operation an error is signalled by the 3 LEDs: see chapter 6.3.
up or during operation an error is signalled by the 3 LEDs: see chapter 6.3.up or during operation an error is signalled by the 3 LEDs: see chapter 6.3.
up or during operation an error is signalled by the 3 LEDs: see chapter 6.3.
 On power
On powerOn power
On power-
--
-up various problems occur on the LCD (strange characters,
up various problems occur on the LCD (strange characters,up various problems occur on the LCD (strange characters,
up various problems occur on the LCD (strange characters, blank display).
blank display).blank display).
blank display).
Check:
1. correct software in the flash;
2. the pLAN address on the pCO and the terminal (compliant with the requirements of the application used);
3. if that the built-in display, is featured, is working correctly; the problem lies in the connection between the pCO and the terminal: make sure that the cable is
plugged in correctly.
 Incorrect reading of the input signals
Incorrect reading of the input signalsIncorrect reading of the input signals
Incorrect reading of the input signals
Check:
1. the correct power supply to the pCO;
2. the correct power supply to the probes: if the voltage (+Vdc>20V) is near zero, disconnect the probe and measure the power supplied by the pCO. If this is
still near zero, turn the controller off and wait a few minutes. If the problem persists, contact CAREL service; otherwise the connection that was removed was
short-circuiting the power supply.
3. the separation of the power supply to the digital inputs from the power supply to the pCO. A 24 Vac/24 Vac transformer with a minimum rating of 5 VA can
be used.
4. that the probe wires are connected according to the instructions;
5. that the probe wires are positioned a sufficient distance from possible sources of electromagnetic disturbance (power cable, contactors, cables with high
voltages and running to devices with high peak current);
6. that there is not a high thermal resistance between the sensor and any probe socket that may be used. If necessary, place conductive paste or oil in the
socket to ensure correct transfer of the temperature;
7. if there is a probe error or a conversion error on the pCO, the checks to be made depend on the type of probe.
 Ac
AcAc
Active humidity probes with 0 to 1 V signal:
tive humidity probes with 0 to 1 V signal: tive humidity probes with 0 to 1 V signal:
tive humidity probes with 0 to 1 V signal: use a voltmeter to check the probe signal between terminals Bn and GND and check that the voltage
corresponds to the value: 1 mVdc corresponds to 0.1% RH
Example:
Example: Example:
Example: reading 200 mVdc (0.2 Vdc), the probe sends a signal that corresponds to 20% RH
• Pressure probes: if errors occur in the reading of these probes, check that:
Pressure probes: if errors occur in the reading of these probes, check that:Pressure probes: if errors occur in the reading of these probes, check that:
Pressure probes: if errors occur in the reading of these probes, check that:
1. the analogue inputs used for the probes are set to accept 4 to 20 mA signals (in the application program);
2. the full scale set via software corresponds to the probes used;
3. the probe capillary is not blocked.
4. Measuring the voltage across terminals Bn and GND gives an indirect indication of the probe signal current, as the input has an impedance of 100Ω,
applying the formula:
I= V/R (2V= 20 mA).
The pressure value “Ps” that the probe is sending can be calculated as follows (FS= Full scale):
Ps= (Vmeas/100 - 0.004) x (FSmax - FSmin) / 0.016 + FSmin
Example: the probe used has FSmin= -0.5 bar, FSmax = 7 bar; the voltage read is equal to Vmeas= 1 Vdc.
The pressure Ps that the probe is measuring is equal to: Ps= (1/100 - 0.004) x [7 - (-0.5)] / 0.016 + (-0.5) = 2.3 bars.
• NTC probes:
NTC probes: NTC probes:
NTC probes: the probe signal is a resistance value that depends on the temperature.
Below are some resistance values at different temperatures. Disconnecting the probe from the input to the interface and measuring its resistance with a multimeter
gives the corresponding temperature, based on the values in the table.
°C
°C°C
°C
K
KK
K
Ω
ΩΩ
Ω
°C
°C°C
°C
K
KK
K
Ω
ΩΩ
Ω
°C
°C°C
°C
K
KK
K
Ω
ΩΩ
Ω
-
20
67.71
0
27.28
20
12.09
-
15
53.39
5
22.05
25
10.00
-
10
42.25
17
17.96
30
8.31
-
5
33.89
15
14.68
35
6.94
When measuring the voltage across terminals Bn and GND, with an NTC fitted, the voltage measured is equal to:
V
IN
= 2.5 x R NTC
10000 + R NTC
Example: inserting a 10 KΩ resistor in the input (corresponding to 25°C) gives:
V
IN
= 2.5 x 10000 = 1.25 V
20000
In the case of the pCO
XS
, the following formula is used:
V
IN
= 5 x R P where R P is the resistance expressed in ohm of the parallel between the resistance of the NTC and 20000 Ω
10000 + R P

Carel pCO1 series Specifications

General

Brand	Carel
Model	pCO1 series
Category	Controller
Language	English