Campbell Scientific A21REL-12 User Manual

INSTRUCTION MANUAL

A21 REL-12 Relay Driver

Revision: 12/91

Copyright (c) 1981-1991

Campbell Scientific, Inc.

Warranty and Assistance

The A21 REL-12 RELAY DRIVER is warranted by CAMPBELL
SCIENTIFIC, INC. to be free from defects in materials and workmanship under
normal use and ser vice for twelve (1 2) months from date of shipment unless
specified otherwise. Batteries have no warranty. CAMPBELL SCIENTIFIC,
INC.'s obligation under this warranty is limited to repairing or replacing (at
CAMPBELL SCIENTIFIC, INC.'s option) defective products. The customer
shall assume all costs of removing, reinstalling, and shipping defective products
to CAMPBELL SCIENTIFIC, INC. CAMPBELL SCIENTIFIC, INC. will
return such products by surface carrier prepaid. This warranty shall not apply
to any CAMPBELL SCIENTIFIC, INC. products which have been subjected to
modification, misuse, neglect, accidents of nature, or shipping damage. This
warranty is in lieu of all other warranties, expressed or implied, including
warranties of merchantability or fitness for a particular purpose. CAMPBELL
SCIENTIFIC, INC. is not liable for special, indirect, incidental, or
consequential damages.

Products may not be returned without prior authorization. The following
contact information is for US and International customers residing in countries
served by Campbell Scientific, Inc. directly. Affiliate companies handle repairs
for customers within their territories. Please visit www.ca mpbellsci.co m to
determine which Campbell Scientific company serves your country. To obtain
a Returned Materials Authorization (RMA), contact CAMPBELL
SCIENTIFIC, INC., phone [phone]. After an applications engineer
determines the nature of the problem, an RMA number will be issued. Please
write this number clearly on the outside of the shipping container.
CAMPBELL SCIENTIFIC's shipping address is:

CAMPBELL SCIENTIFIC, INC.

RMA#_____
815 West 1800 North
Logan, Utah 84321-1784

CAMPBELL SCIENTIFIC, INC. does not accept collect calls.

A21 REL-12 RELAY DRIVER

FUNCTION:

Provide drive capability for four external relays
controlled by the CR10, 21X, or CR7
dataloggers. The A21 REL-12 is powered by a
12 V source on the relay coil.

CONTACT RATING:

DC - 1 Amp at 20 V
AC - 0.3 Amp at 120 V

COIL CURRENT:

13 mA/relay

CONNECTIONS:

+12 V External 12 V source
Ground Low side of external source
REL COM Low side of device under control
REL NC Normally closed relay output to

device under control

CTRL To datalogger control port. When

presented with 5 V, REL NC and
REL NO invert their normal states
until CTRL goes to 0V at which time
REL NC and REL NO return to
normal states.

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