CA 32

Current input conditioners

 

General

The conditioners of the CA-32 family with current mili-Amper and Amper inputs are isolated single channel signal conditioner modules converting the input signal from current to voltage or other current span, amplifying, protecting, filtering and isolating the signal. A conditioned signal is then fed to a data acquisition system, an Industrial PC, a PLC, or to another measuring system.

Isolation conditioners protect people and measuring equipment by galvanicly separating the system from the events that can occur on the side of the signal source or elsewhere in a measured environment. The module input is protected from transients and voltage levels up to 250 Vrms continuously. The isolation voltage is 1.500V

The CA-32 module series can be mixed within the same application with other series of isolation modules. They can be connected on to the measuring system without switching off the power supply or system shutdown (hot swapable).

There are a large number of models available to users on the page: Prices and models CA-32

 

Attributes

  • Instrumentation accuracy, linearity, repeatability and reliability
  • Current mAmp or Amp input - voltage or current output
  • Voltage output: 0 to 5 V, 0 to 10 V; ± 5 V; and ± 10 V, or
  • Current output: 0 to 20 mA, 4 to 20 mA, ± 5 mA, ± 10 mA, ± 20 mA
  • Triple transformer insulation input-output-power 1.500V
  • ± 0.03% Accuracy
  • ± 0.01% Linearity
  • 80 dB NMR for 50 Hz
  • 110 dB CMR
  • Input continuously protected up to 250 V
  • The power supply of the conditioner is from 24V DC or 220V AC nominal
  • Protection by ANSI / IEEE C37.90.1-1989 specification
  • Mounting on DIN rail
  • The warranty period is 7 years, and the service period is 10 years
 

 

Simplified diagram of CA-32

Characterization

The CA-32 at the input has a resistor on which the voltage is measured by a chopper differential amplifier with low temperature drift, low offset and a very stable gain temperature coefficient. Differential amplifier does not require input grounding. On the front of the module below the mask there are two multi-turn trimmers for precise adjustment of the offset and the gain. Both values ​​are factory-set and the user can override them if there is a need for it.

The central component of the module is a signal isolation transformer. Like most transformers, this has a primary and secondary side. Using this terminology, the input side of the module is the "primary side" and the output side of the module is called the "secondary side". A sensor connector is connected to the primary side of the module, and the secondary side of the module is connected to the data acquisition and measurement system, to the analog input module of the Industrial PC or PLC, to a panel meter or to another measurement system.

Transformer signal isolation uses a method of amplitude modulation to obtain linear, stable and reliable characteristics. This technique provides better results than the technique with digital or linear opto-scanners or a condenser isolation technique. The primary side of the module is galvanically isolated or "floating" in relation to the secondary side of the module and in relation to the el. power supply. The signal demodulator on the secondary side of the module restores the original signal, which is then filtered and buffered to achieve a low noise level and low impedance output signal.

The CA-32 Series Insulation Modules have a fifth-line filter built-in, with the first Anti-Aliasing pole located in the primary module module while the fourth-row filter is located on the secondary side of the isolation barrier. After the Anti-aliasing filtering, the signal is fed to the chopper level behind the specially designed micro transformer. In the secondary stage, behind the isolation barrier, the signal is demodulated and filtered again by the transmissions and interference. The output from the module can be, if necessary, a voltage or current signal.

The warranty period is 7 years and the service period is 10 years. It is delivered with a user manual and with a calibration list.

 

CA-32 with 110 / 220V AC power supply (option)

The basic version of the CA-32 works with a standard DC power supply of 19 to 30V DC (24V DC nominal). However, if the application requires the power supply of a 220V AC coder, which is not a rare case, then the user can order a conditioner with the suffix A.

This type of conditioner works with an alternating voltage of 85 to 265V or with a DC voltage of 100 to 400V. These two power supplies make the CA-32 applicable in many situations. Some users use these conditioners in an environment that is powered by a 110V battery, or in elevated AC voltage conditions.

On this conditioning model, there are three terminals for connecting the power supply: L, N and GND (Picture on the left). The L should connect the phase, to N, and to the GND ground. Grounding, apart from the safety function, has the function of reducing the internal voltage unit oscillations, so it should be connected in any case. If the DC power supply is used, it must be connected to the L and N connectors (the schedule is not relevant).

Relay(option)

The family of isolating conditioners CA-32 with suffix R has a relay with a working and quiet contact on the external terminals. The relay can switch on or off to 240V, 6A, and can be set to activate when the input size is greater than the specified value or when the input size is less than the set value. On the copies there is a working and quiet contact. The relay has a built-in hysteresis control that can be fine tuned with a precision multi-port trimmer potentiometer.

The only limitation for this version is that if it is used with 220V power supply (version with suffix A), the relay has only a working contact.

The setting of the relay activation level is performed by the potentiometer on the front of the conditioner. In order to avoid the oscillation of the relay when the input size is the same, the hysteresis is assigned to the device. Hysteresis in the first case, when the relay is activated and when the input is greater than the set value, indicates the size of how much the input size should be smaller than the specified relay activation size for it to be turned off. In the second case, it indicates how much the input size should be to be higher than the set to switch off the relay. Hysteresis can be set to 1% or 5% span with an internal jumper.

If the load is applied to the relay of the inductive character, it is necessary to add the "snubber" from the outside in parallel to the relay contacts. The values ​​of the supply components are calculated, but can also be determined empirically for the given application. Generally, even if the load is applied to the relay of the inductive type, a capacitor of 0.2 uF per line with a 10 Ohm resistor can be used. For optimum performance, the supply wheel must be calculated because this is the best way to optimally extinguish the spark at the relay.

Power supply and T-BUS connector

For the power supply of a smaller number of conditioners up to 20, a CS-24-48 that delivers 48W is recommended (picture on the left), and for greater number of conditioners a CS-24-90 of 90W should be used. Both models can, via the T-BUS connector be connected, directly, without wiring to power the conditioners on the same, or with the extension cable, on different DIN rails in a closed environment. This option raises reliability, greatly reduces the time of replacement of the conditioner and allows the conditioner to be connected or disconnected while the T-BUS is powered up.

Both power supplies work in a wide voltage range: CS-24-90 from 160V to 265V AC, while smaller, CS-24-48 can operate as much as 85V to 265V. If users do not want to use this type of power supply, they can also use other power supplies, but in this case, the power supply must be wired from one conditioner to the other by cables.

Picture on the left: Power supply CS-24-48 for conditioners with T-BUS connector

 

The printed circuit board of the conditioner on request can be protected with special lacquer which protects electronic components from moisture, corrosion and other types of contamination, which can significantly extend the life of this product and in terms of long-term measurement accuracy. When conditioner is prepared in this way it can be applied in many aggressive environments. For example: on ships or on the seashore, in conditions of aggressive vapors, and other places with high humidity, etc...

 

Specifications

Typical (25°C)

 Parameter CA-32

 Input

 Input resistance for span up to 20mA 47 Ω tol  0.1%, ±25 ppm/°C
 Input resistance for span from 50mA to 200mA  1Ω  tol 1%, ±50 ppm/°C
 Input resistance for span from 1A 0,01Ω tol 1% ±50ppm/°C
 Input span  ±5mA do 0÷10A
 Input protection - continuous (except shunt resistor) 250Vrms max.
 Ulazna protection - transients ANSI/IEEE C37.90.1- 1989

 Output

Short-circuit protection Continuous
 Current limit (Iout max.) 5 mA (Vout), 30 mA (Iout)
 Rise Time, 10% to 90% of span 8 ms
 Transient protection ANSI/IEEE C37.90.1- 1989
 Adjustment range ±1,5% offset and ±5% gain (span) - typ.

 Accuracy

 Accuracy ±0.03% of span
 Linerity ±0.01% of span

 Input offset stability

±0.5 ÷ ±5µV/°C, depending on model
 Output offset stability ±5ppm/°C (Vout), ±15ppm/°C (Iout)
 Gain stability Better then ±50ppm/°C
 Output noise100 KHz 200µVrms (Vout) i 1µArms (Iout)
 Standard frequency range (-3 dB) 100Hz
 NMR 80dB
 Isolation
 CMV, Out-power 1000 V
 CMV, In-Out, In-power 1500 V  (4 kV 1 minut)
 CMR 50Hz  110 dB
 Power supply
 Voltage 19 V to 30 V DC
 Current consumtion 26 mA (Vout) i 48 mA (Iout)
 Reverse polarity protection Continuous
 Transient protection ANSI/IEEE C37.90.1- 1989
 Environment and dimensions
 Temperature range (specifications) -25 +80°C
 Working temperature range -40 +85°C
 Storage temperature range -40 +85°C
 Humidity Non-condensing 0 to 95%
 Mounting rail DIN EN50022   -35 x 7,5;  -35 x 15
 Dimensions (mm) 114,5 x 22,5 x 99

 

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