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|---|---|
| Repair | Yes | 
| Free Support | Yes | 
The SDM-SW8A increases the number of switch closures or voltage pulses a datalogger can measure. Sensors that output a switch closure or voltage pulse signal include tipping bucket rain gages, flow meters, and anemometers.
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							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.
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.
Nota: lo siguiente muestra información de compatibilidad notable. No es una lista de todos los productos compatibles.
| Producto | Compatible | Nota | 
|---|---|---|
| 21X (retired) | ||
| CR10 (retired) | ||
| CR1000 (retired) | ||
| CR1000X (retired) | ||
| CR10X (retired) | ||
| CR200X (retired) | ||
| CR216X (retired) | ||
| CR23X (retired) | ||
| CR300 (retired) | ||
| 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) | 
| Producto | Compatible | Nota | 
|---|---|---|
| GRANITE 10 | ||
| GRANITE 6 (retired) | ||
| GRANITE 9 | 
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).
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.
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.
| 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) |