For switch closure or voltage pulse sensors
Overview
Your datalogger 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 datalogger
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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 datalogger enables individual modules through an addressing scheme; multiple SDMs (in any combination) can be connected to one datalogger. We recommend a maximum of four SDM-SW8As be connected to a single datalogger. After a module is enabled, it operates independently of the datalogger until additional commands are received or results are transmitted.
Specifications
| 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 Voltage | 9.6 to 16 V |
| Typical Current Drain |
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| Operating Temperature | -25° to +55°C |
| 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
Datalogger Considerations
Programming
In the CRBasic dataloggers, the SDM-SW8A operation is controlled by the SDMSW8A instruction. Instruction 102 controls the SDM-SW8A operation for Edlog dataloggers that were shipped after October 1988 (consult Campbell Scientific for equipment shipped prior to this date).
Compatible Contemporary Dataloggers
| CR200(X) Series | CR800/CR850 | CR1000 | CR3000 | CR9000X | CR6 |
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Compatible Retired Dataloggers
| CR500 | CR510 | CR10 | CR10X | 21X | CR23X | CR5000 | CR7X | CR9000 |
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Datalogger Notes:
*For the CR3000 and CR5000, SDMs are connected to the ports labeled SDM-C1, SDM-C2, and SDM-C3.
**For the CR7X, SDMs connect to the C1, C2, and C3 terminals provided on the CR700X control module (after Sept 1996).
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 datalogger power supply. You can do this where ac power is available, or where a solar panel can be used for recharging the datalogger'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.
Compatible Enclosures
| ENC10/12 | ENC10/12R | ENC12/14 | ENC14/16 | ENC16/18 | ENC24/30 | ENC24/30S |
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Cofely Fabricom NV/SA (GDFSuez) has utilized Campbell Scientific equipment on numerous projects in both the......read more