Pulse Input Adapters (Part #: S-UCC-M00x and S-UCD-M00x)
for use with HOBO® H21, H22, and U30 Series Data Loggers
The Pulse Input Adapters are used to log the number of switch closures per
interval and are designed to work with smart sensor-compatible HOBO data
loggers. The adapter has a plug-in modular connector that allows it to be added
easily to these loggers.
Two versions are available:
• Mechanical contact closure (S-UCD-M00x). Ideal for connecting
tipping-bucket rain gauges to HOBO H21 series loggers or U30 series
loggers.
• Solid-state electronic switches (S-UCC-M00x). Used for connecting
compatible pulse output sensors to HOBO H22 or U30 series loggers.
Inside this package
• Pulse Input Adapter
• 2 wire nuts
Specification Pulse Input Adapter
S-UCC-M00x
for Electronic Switches
Maximum Input Frequency 120 Hz (120 pulses per second) 2 Hz (2 pulses per second)
Measurement Range 0 – 65,533 pulses per logging interval
Resolution 1 pulse
Lockout time 45 µs ± 10% 327 ms ± 10%
Recommended Input Type
Preferred Switch State† Active low input Normally open
Edge Detection Falling edge, Schmitt Trigger buffer (logic levels: low ≤ 0.6 V, high ≥ 2.7 V)
Minimum Pulse Width 1 ms
Input/Output Impedance 100 KΩ
Open Circuit Input Voltage 3.3 V
Maximum Input Voltage 3.6 V
User Connection 24 AWG wires, 2 leads: white(+), black(-)
Operating Temperature Range -40° to 75°C (-40° to 167°F)
Overall Cable Length 6.5 m (21.3 ft.) or 1.57 m (5.1 ft.)
Length of Smart Sensor Cable 50cm (1.6 ft.)
Housing Weatherproof Xenoy housing protects input adapter electronics
Housing Dimensions 12.7 x 2.9 cm (5 x 1.13 in.)
Weight S-UCx-M001: 114 g (4 oz.); S-UCx-M006: 250 g (9 oz)
Bits per Sample 16
Number of Data Channels 1
Measurement Averaging Option No (reports the number of pulses over the logging interval)
Part Number S-UCC-M001 (1 m), S-UCC-M006 (6 m) S-UCD-M001 (1 m), S-UCD-M006 (6 m)
†
For maximum battery life, the Pulse Input Adapters should be used with their preferred switch type. The
Electronic solid state switch closure or
CMOS-level digital output (example: FET,
opto-FET or open collector)
The CE Marking identifies this product as complying with the relevant directives in the
European Union (EU).
Mechanical contact closure (example: reed
switch in a tipping-bucket rain gauge)
S-UCD-M00x
for Contact Closures
adapters will work with active high inputs (S-UCC) and normally closed switches (S-UCD), but battery life
will not be optimized.
© 2010–2013 Onset Computer Corporation. Onset and HOBO are registered trademarks of Onset Computer Corporation.
Other products and brand names may be trademarks or registered trademarks of their respective owners.
Part #: MAN-S-UCx
Doc #: 13577-D
Pulse Input Adapters
Input Connections
The Pulse Input Adapter sensor has two input connections. The white wire (+) is powered at 3.3 V through a 100 KΩ resistor.
This power is supplied from the logger’s battery. The black wire (-) is connected through the adapter to the logger’s ground
connection. The input cable can be connected directly to screw terminals on the sensor or to sensor cables with the included
wire nuts.
Connection using Wire Nuts
IMPORTANT: If using wire nuts, make sure the connection is protected from the elements.
1. Strip 1 cm (3/8") of insulation from the end of wires, taking care not to nick the metal conductors.
2. Twist the stripped wires together clockwise and then screw on the wire nut clockwise.
3. Check the connection by gently pulling on the wires to verify a solid mechanical connection. Always strain-relief
the connection to make sure that the connection is not broken by being jerked or repeatedly worked back and forth.
Connecting to the Logger
To start using the Pulse Input Adapter, stop the logger and insert the adapter’s modular jack into an available sensor
connection port on the logger. For expansion options, see the logger’s user manual.
The logger automatically detects the new input adapter the next time you launch it. Launch the logger and verify that the
Pulse Input Adapter is functioning correctly. Refer to the logger’s user guide for more details about connecting HOBO smart
sensors.
Mounting
To provide long-term protection from moisture entry, the smart sensor adapter must be mounted horizontally and with the
cable wires routed with drip loops so that water drains away from the cable entry point as shown in the example below. When
mounted properly, the housing is weatherproof (but not waterproof).
Smart sensor adapter
mounted horizontally
Drip loop
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Drip loop
Pulse Input Adapters
Maximizing Battery Life
The Pulse Input Adapters consume about 1 µA of current with the input high (switch open) and about 33 µA with the input
low (switch closed). For maximum logger battery life, use the Pulse Input Adapters with normally open switches or with
transducers that are off (circuit open) for 90% of the time or longer.
Third-party Sensors
When making a connection to a third-party sensor, take time to make sure that the connection is reliable. The connection
should be protected from rain, dirt, and direct exposure to the elements. Third-party sensors purchased from Onset, such as
WattNode
®
or Veris pulse output kWh transducers, are supplied with documentation that provides additional information for
system configuration.
Verifying Functionality
To verify proper operation of the Pulse Input Adapter, connect the adapter to a logger and launch the logger. For the S-UCDM00x model, enter a known number of pulses (for example, if using a tipping-bucket rain gauge, tip the bucket several
times). Then read out the logger and verify that the number of pulses in the data file is correct.
If you think either the S-UCC-M00x or S-UCD-M00x model is not capturing pulses, check the connections to the adapter and
verify the device being measured is functioning normally. If you believe the adapter is not working properly, you can send
the adapter back to Onset for repair. Contact Onset or your Onset Authorized Dealer for a Return Merchandise Authorization
(RMA) number.
Using the S-UCD-M00x Adapter (for Contact Closures)
This section describes using the S-UCD-M00x to connect the H21-001, H21-002, or U30 Station to a device with a
mechanical contact closure.
Guidelines
• The adapter housing should be installed outside the logger enclosure. Be sure to follow the instructions included with the
logger to ensure that the logger is properly sealed where the sensor cable exits the logger enclosure.
• Secure the adapter housing to the mast or sensor mounting arm. Excess cable should be coiled and secured with cable
ties.
• If sensor cables are left on the ground, use a conduit to protect against such things as animals, lawn mowers and
exposure to chemicals.
Example: Tipping Bucket Rain Gauge or Mechanical Contact Closure
The S-UCD-M00x is designed to work with tipping-bucket rain gauges and other devices with normally open, mechanical
contact closure, switched outputs with a maximum pulse frequency of 2 Hz. This sensor has a pre-set lockout time of 327 ms
and is designed to work with signals that must be de-bounced to be accurately measured.
A typical setup for connecting a sensor with a mechanical contact closure is shown below.
S-UCD-M00x Example
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Pulse Input Adapters
De-bouncing
“Bounce” is a phenomenon where a single pulse may contain several false pulses or bounces. De-bouncing a signal is
typically required when measuring signals from mechanical switches, contact closures, and reed switches.
The lockout time prevents bounce-induced false pulses from being counted as separate switch closures. If your gauge has a
counter display and battery, disconnect them and connect the Pulse Input Adapter in their place. In most cases, the black and
white wires can be connected directly to the relay output. (When connecting to relay or switch contacts, polarity does not
matter.)
Using the S-UCC M00x Adapter (for Electronic Switches)
This section describes using the S-UCC-M00x to connect the H22-001 or U30 Station to a device with an electronic switch.
Example: FET Switch Transducer
The 120 Hz Pulse Input Adapter (S-UCC-M00x) is designed for devices with a normally open solid-state switch, FET switch
or open collector, with a maximum pulse frequency of 120 Hz. This input adapter will not work with sensors that have
mechanical switch outputs, AC outputs, or outputs that must be de-bounced (see previous section).
A typical setup of a FET switch transducer is shown below.
S-UCC-M00x Example
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