This product is no longer available and has been replaced by: SDM-IO16A. Some accessories, replacement parts, or services may still be available.
| Services Available | |
|---|---|
| Repair | Yes |
| Free Support | Yes |
Overview
Your data logger can measure more switch closures or voltage pulses with an SDM-SW8A. Sensors that output a switch closure or voltage pulse signal include tipping bucket rain gages, flow meters, and anemometers.
Read MoreBenefits and Features
- Well suited for use in energy management studies
- Provides eight individually configured channels
- Measures a variety of signals: reed switches, dry contacts, or slow voltage pulses
- Allows up to four SDM-SW8As to be connected to a single data logger
Feature comparison of the retired SDM-SW8A and its replacement, the SDM-IO16A:
| Feature | SDM-SW8A | SDM-IO16A |
|---|---|---|
| Input/Output | In | In and Out |
| Channel Count | 8 | 16 |
| State In | Y | Y |
| State Out | N | Y |
| Counts | Y | Y |
| Frequency | N | Y |
| Switch | Y | Y |
| Duty Cycle | Y | Y |
| Interrupt | N | Y |
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Detailed Description
The SDM-SW8A provides eight channels for connecting the sensors. Each channel is individually configured for single-pole double-throw (SPDT), single-pole single-throw (SPST), or voltage pulse measurements. Output options include counts, duty cycle, and state.
SDM Operation
The data logger enables individual modules through an addressing scheme; multiple SDMs (in any combination) can be connected to one data logger. We recommend a maximum of four SDM-SW8As be connected to a single data logger. After a module is enabled, it operates independently of the data logger until additional commands are received or results are transmitted.
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Specifications
| Function | Increases the number of switch closures or voltage pulses a data logger can measure. |
| Number of Channels | 8 |
| Measurement Types | Switch closure (SPDT, SPST), dc voltage pulse |
| Input Voltage Threshold | From below 0.9 to above 4.0 Vdc (±20 Vdc maximum) |
| Maximum Input Frequency | 100 Hz (50% duty cycle) |
| Minimum Input Pulse Width | 5 ms high, 5 ms low |
| Maximum Bounce Time | 3 ms open without counting |
| Output Options | State, duty cycle, counts |
| Maximum Count/Port | 65535 |
| Internal Sampling Frequency | 500 Hz |
| Watchdog Reset | Yes |
| Operating Temperature | -25° to +55°C |
| Operating Voltage | 9.6 to 16 V |
| Typical Current Drain |
|
| Relative Humidity | 0 to 90% RH (non-condensing) |
| Maximum Cable Length |
6 m (20 ft) total to all SDM devices Consult Campbell Scientific if longer lengths are necessary. |
| Dimensions | 15.7 x 6.9 x 2.3 cm (6.2 x 2.7 x 0.9 in.) |
| Weight | 0.23 kg (0.5 lb) |
Compatibility
Please note: The following shows notable compatibility information. It is not a comprehensive list of all compatible products.
Data Loggers
| Compatible | Note | |
|---|---|---|
| 21X (retired) | ||
| CR10 (retired) | ||
| CR1000 (retired) | ||
| CR1000X | ||
| CR10X (retired) | ||
| CR200X (retired) | ||
| CR206X (retired) | ||
| CR23X (retired) | ||
| CR295X (retired) | ||
| CR300 | ||
| CR3000 (retired) | For the CR3000, SDMs are connected to the ports labeled SDM-C1, SDM-C2, and SDM-C3. | |
| CR310 | ||
| CR500 (retired) | ||
| CR5000 (retired) | For the CR5000, SDMs are connected to the ports labeled SDM-C1, SDM-C2, and SDM-C3. | |
| CR510 (retired) | ||
| CR6 | ||
| CR800 (retired) | ||
| CR850 (retired) | ||
| CR9000 (retired) | ||
| CR9000X (retired) |
Distributed Data Acquisition
| Compatible | Note | |
|---|---|---|
| GRANITE 10 | ||
| GRANITE 6 | ||
| GRANITE 9 |
Additional Compatibility Information
Data Logger Considerations
Programming
In the CRBasic data loggers, the SDM-SW8A operation is controlled by the SDMSW8A instruction. Instruction 102 controls the SDM-SW8A operation for Edlog data loggers that were shipped after October 1988 (consult Campbell Scientific for equipment shipped prior to this date).
Power Supply
Due to the 3 mA continuous and 6 mA active current drain, an auxiliary 12 Vdc power supply is recommended for powering the SDM-SW8A in remote, long-term applications.
For some applications, it may be convenient to use the data logger power supply. You can do this where ac power is available, or where a solar panel can be used for recharging the data logger's sealed rechargeable battery.
Enclosure Considerations
The SDM-SW8A requires a desiccated, non-condensing environment; a Campbell Scientific enclosure is recommended. Grommets and screws are provided to attach the SDM-SW8A to the backplate of our enclosures.