Campbell AM416, Instruction Manual

AM416 RELAY MULTIPLEXER

3

3.  AM416 SPECIFICATIONS

POWER*:

  unregulated 12 VDC (9.6 V to 16 V)

- See Figure 4 for implications of low power to
relay actuation

CURRENT DRAIN:

Quiescent:  < 100 uA
Active:  17 mA (typical)

RESET*:

  a continuous signal of 3.5VDC <

voltage < 16 VDC holds AM416 in an active
state (i.e. a clock pulse can trigger a scan
advance).  A signal voltage of < 0.9VDC
deactivates the AM416 (clock pulse will not
trigger a scan advance; AM416 is also reset).

CLOCK*:

  on the transition from <1.5 V to >3.5

V, scan advance is actuated on the leading
edge of the clock signal; clock signal must be a
minimum of 5 ms in width.

OPERATIONAL TEMPERATURE:

  -40oC to

+65oC

OPERATIONAL HUMIDITY:

  0 - 95%, non-

condensing

DIMENSIONS

 (without field enclosure):

length - 21 cm (8.2")
width  - 16.5 cm (6.5")
depth  -  3.5 cm (1.5")

(with field enclosure i.e. box size):
length - 25.4 cm (10.0")
width  - 20.3 cm (8.0")
depth  - 10.2 cm (4.0")

WEIGHT:

  1.5 lbs (approx.)

(in enclosure):  10.0 lbs (approx.)

EXPANDABILITY**

(nominal):

3 AM416'S/CR10(X)
4 AM416'S/21X
8 AM416's/CR7 725 Card

MAXIMUM CABLE LENGTH:

  sensor & scan

rate dependent (in general, longer lead lengths
necessitate longer measurement delays.  Refer
to datalogger manual for additional details).

MAXIMUM SWITCHING CURRENT***:

  500 mA

* Reset, Clock, and +12V inputs are limited to
+16V by 1.5KE20A transzorbs.

** Assumes sequential activation of multiplexers
and that each datalogger channel is uniquely
dedicated.  If your application requires
additional multiplexing capability, please consult
CSI for application assistance.

*** Switching currents greater than 30 mA
(occasional 50 mA is acceptable) will degrade
the contact surfaces of the mechanical relays
(i.e. increase their resistance).  This process will
adversely affect the suitability of these relays to
multiplex low voltage signals.  Although a relay
used in this manner will not be of use in future
low voltage measurements, it may continue to be
used for switching current in excess of 30 mA.

CONTACT SPECIFICATIONS

Initial contact resistance:  50 mohm max.
Initial contact bounce:  1 ms max.
Contact material:  Gold clad silver alloy
Electrostatic capacitance:  3pF
Minimum expected life:

Mechanical (at 50cps):  108 open
Electrical (at 20cps):  2 x 105

CHARACTERISTICS (at 25oC, 50% Relative
Humidity)

Operate time   8 to 15 ms approx.  (See Figure 4)
Release time   5 ms approx.

4.  OPERATION

Subsection 4.1 discusses the use of the
terminals that control operation of the
multiplexer.  These terminals are located along
the lower left side of the multiplexer as shown in
Figure 1.  Subsection 4.2 discusses the use of
terminals used in sensor measurement.

4.1.  THE CONTROL TERMINALS

The CR10(X), 21X and CR7 dataloggers should
be connected to the AM416 as shown in Figure
2.  This figure depicts control connections;
measurement connections are discussed in
Section 6.  The power, ground, reset, and clock
connections remain essentially the same
regardless of datalogger used.

In a CR10(X) application, the datalogger 12VDC
supply and ground terminals are connected to
the AM416 12V and ground terminals. Two
control ports are used for clock and reset.