The A21REL-12 contains four internal relays that allow a Campbell Scientific datalogger to control up to four external ac or dc devices.
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				The A21REL-12's internal relays are single-pole double-throw. This relay driver may be powered by the datalogger power supply or a separate 12 Vdc battery.
Número de FAQs relacionadas con A21REL-12: 1
The following relay devices can be used with the CR800 and the CR850:
The CR800 and the CR850 can also be used with a wide variety of third-party relay devices.
*Because the CR800 and the CR850 only have four digital ports, they do not have the ability to switch all six of the relays on the A6REL-12.
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) | ||
| CR10X (retired) | ||
| CR200X (retired) | ||
| CR216X (retired) | ||
| CR23X (retired) | ||
| CR300 (retired) | ||
| CR3000 (retired) | ||
| CR310 | ||
| CR350 | ||
| CR500 (retired) | The CR500 has only one control port capable of providing a control signal. | |
| CR5000 (retired) | ||
| CR510 (retired) | The CR510 has only one control port capable of providing a control signal. | |
| CR800 (retired) | ||
| CR850 (retired) | ||
| CR9000 (retired) | ||
| CR9000X (retired) | 
Each of the four relays is controlled by a data logger control port.
| Cable(s) Used | Number of Relays Controlled | 
| One CABLE3CBL-L | 1 | 
| One CABLE4CBL-L | 2 | 
| One CABLE5CBL-L | 3 | 
| Two CABLE3CBL-L | 4 | 
The A21REL-12 may be powered by the data logger power supply or a separate 12 Vdc battery.
The A21REL-12 requires a non-condensing environment. No mounting bracket is available. The peripheral is typically mounted in the data logger enclosure with double-sided tape or Velcro.
| Function | Allows a data logger to control up to four external ac or dc devices. | 
| Number of Channels | 4 | 
| Contact Ratings | 
									
										
  | 
							
| Coil Current | 13 mA/relay | 
| Relays | dual single-pole, double-throw relays | 
| Operating Temperature | -25° to +50°C | 
| Operating Voltage | 12 Vdc | 
| Dimensions | 14.0 x 6.9 x 3.0 cm (5.5 x 2.7 x 1.2 in.) | 
| Weight | 227 g (8 oz) |