SDM-CVO4 Módulo de salida corriente/voltaje 4 canales
Salidas en voltaje u corriente
Expande la capacidad de salida de voltaje/corriente del datalogger
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El SDM-CVO4 se conecta al datalogger y saca niveles de voltaje u corriente bajo control del datalogger. Las aplicaciones típicas son por ejemplo para pasar valores a pantallas que funcionen por lazo de corriente, retransmitir valores medidos por el datalogger a sistemas de control industrial, envío de señales de control a válvulas y proporcionar excitación de voltaje/corriente a sensores externos.

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Ventajas y características

  • Expande la capacidad del datalogger con salidas en corriente/voltaje
  • Proporciona cuatro salidas de corriente o voltaje independientes
  • Da señal a visualizadores remotos basados en lazo de corriente
  • Retransmite valores medidos a sistemas de control industrial que dispongan de entradas en corriente o voltaje alto
  • Envía señales de control a electroválvulas
  • Proporciona voltajes de excitación o de corriente a sensores externos


Descripción técnica

El SDM-CVO4 dispone de cuatro canales de salida para conexión a dispositivos externos. Proporciona salidas de voltaje o corriente variables bajo control del programa de adquisición del datalogger. Las salidas están aisladas tanto del datalogger como de las otros canales del SDM-CVO4, lo cual evita problemas de lazos de tierra. El datalogger puede fijar las salidas de 0 a 10Vdc o de 0 a 20mA (la salida en corriente admite también escalado de 4 a 20mA).

En modo corriente, la salida tanto puede actuar como controlador de corriente a dos hilos (donde el lazo se alimenta desde una fuente externa), o generar una corriente de 0 a 20 mA usando una salida en voltaje derivada de la propia fuente de alimentación del módulo.


El SDM-CVO4 dispone de una barrera de aislamiento interna con protectores contra transitorios de hasta 1500Vac (rms), 2500Vdc nominal. El aislamiento es entre cualquiera de las salidas y la tierra del SDM-CVO4, y también entre los propios canales.

Incluye componentes de protección, que saltarán de forma controlada en valores cercanos a ese límite (para más detalles ver manual Sección 4.5).


Operating Temperature -25 to +50°C
Operating Voltage 12 Vdc nominal (8 to 16 V)
Minimum Voltage Drop 2.5 V (@ 20 mA current flow) across the internal current regulating circuit
Maximum Input Voltage 20 Vdc (relative to channel ground)
EMC Status Complies with EN55022-1:1998 and EN50082-1:1998.
  • 17.8 x 10.2 x 2.3 cm (7.0 x 4.0 x 0.9 in.) without mounts
  • 23.4 x 11.2 x 2.3 cm (9.2 x 4.4. x 0.9 in.) with mounts
Weight 363 g (13 oz)


Tested Isolation Each channel of each unit is tested for isolation resistance at 500 Vdc.

Pass level > 10 MΩ
Maximum Recommended Continuous Operating Voltage 240 Vac rms differential between an output and data logger ground, providing all issues relating to local regulations for safe installation and operation are followed (Refer to Section 4.5 Safety Considerations in the Instruction Manual.)

Current Mode

Range 0 to 20,000 µA
Resolution 5 µA
Minimum Output Current (leakage) 5 µA (at +50°C)
Accuracy at +23°C ±0.02% of set current + (±5 µA)
Typical Accuracy at -25° to +50°C ±0.1% of set current + (±5 µA)
Worst Case Accuracy at -25° to +50°C ±0.15% of full scale range + (±5 µA)

Voltage Mode

Range 0 to 10,000 mV
Resolution 2.5 mV
Maximum Output Current 30 mA per channel
Minimum Load Current 5 µA if output < 200 mV
Accuracy at +23°C ±0.02% of set voltage + (±2.5 mV)
Accuracy at -25° to +50°C ±0.13% of set voltage + (±2.5 mV)

Current Drain @ 12 Vdc

Typical Active Current 27 or 54 mA, depending on operating mode (no load on output ports)

To estimate the total current, add the active current to the sum of all output currents multiplied by 1.5. For example, if each port is at 10 mA output, the total = 54 + (1.5•4•10) = 114 mA.
With All Outputs Off < 0.5 mA


Please note: The following shows notable compatibility information. It is not a comprehensive list of all compatible products.


Product Compatible Note
CR200X (retired)

Equipos para montajes

Product Compatible Note


Product Compatible Note
21X (retired)
CR10 (retired)
CR10X (retired)
CR216X (retired)
CR23X (retired)
CR3000 For the CR3000, SDMs are connected to the ports labeled SDM-C1, SDM-C2, and SDM-C3.
CR500 (retired)
CR5000 (retired) For the CR5000, SDMs are connected to the ports labeled SDM-C1, SDM-C2, and SDM-C3.
CR510 (retired)
CR9000 (retired) Although the CR9000 is compatible, the SDM-CVO4 does not support its fastest communication rates and therefore may not be practical for CR9000 applications.
CR9000X Although the CR9000X is compatible, the SDM-CVO4 does not support its fastest communication rates and therefore may not be practical for CR9000X applications.

Información de compatibilidad adicional


The SDMCVO4 instruction controls the SDM-CVO4 operation in CRBasic; Instruction 103 controls the SDM-CVO4 operation in Edlog.

Power Considerations

The SDM-CVO4 power requirements are large compared to most Campbell Scientific products—especially when driving significant loads. Care must be taken to ensure the power supply can deliver this higher demand. Alkaline batteries are not recommended for long-term applications.

The SDM-CVO4 has two internal power supplies—one for channels 1 and 2, and one for channels 3 and 4. The power supply for channels 3 and 4 is only turned on if the data logger sends an instruction that sets the output of those channels. If channels 3 and 4 are not used, the power consumption is approximately 20 mA lower than when all outputs are used.

Where supported by the data logger, and when the application allows it, the SDM-CVO4 can be shut down to reduce its power consumption to less than 0.5 mA. In this state, all outputs are switched off.

Enclosure Considerations

The SDM-CVO4 requires a desiccated, non-condensing environment; a Campbell Scientific enclosure is recommended. A mounting bracket, grommets, and screws attach the SDM-CVO4 to the backplates of a Campbell Scientific enclosure.

Preguntas frecuentes

Número de FAQs relacionadas con SDM-CVO4: 5

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  1. The SDM-CVO4 allows most Campbell Scientific data loggers to produce a value by whatever means measured or derived as a scaled 0 to 20 or 4 to 20 mA signal (four terminals).

    The data logger sends an instruction to the SDM-CVO4 with the voltage or current to be transmitted to the other device. The SDM-CVO4 does not itself convert a voltage to a current. A data logger is needed to make a measurement and instruct the SDM-CVO4 as to what the output should be. 

  2. To get continuous analog outputs, either the SDM-AO4A (four channels, non-isolated, voltage only) or the SDM-CVO4 (four channels, isolated, voltage or current) is needed. Multiples of those devices can be used to acquire more outputs.
  3. Yes. Up to 15 SDM devices can be attached to a datalogger because they are addressable with a hex number of 0 to F.  Some of those devices may require more power, which would need to be considered when adding devices.

  4. For the CR1000, to get continuous analog outputs, an SDM-AO4A (4-channels, non-isolated, voltage only) or an SDM-CVO4 (4-channels, isolated, voltage or current) is needed. Multiples of these devices can be used to get more outputs.  For single channels of output, some third-party devices can be used.

  5. Yes. The CR3000 and CR5000 have two native Continuous Analog Output channels. The SDM-AO4A (voltage) or SDM-CVO4 (voltage or current) can also be used.

Casos de aplicación

Louisiana: Sinkhole Monitoring
In August 2012, RESPEC was contracted to provide field instrumentation and early-warning monitoring services at......leer más