Campbell SDM-CVO4 User manual

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SDM-CVO4
4-
Channel Current and
Voltage Output Module
Revision: 06/2020
Copyright © 2001 – 2020
Campbell Scientific
CSL I.D - 436

Guarantee
This equipment is guaranteed against defects in materials and workmanship.
We will repair or replace products which prove to be defective during the
guarantee period as detailed on your invoice, provided they are returned to us
prepaid. The guarantee will not apply to:

Equipment which has been modified or altered in any way without the
written permission of Campbell Scientific

Batteries

Any product which has been subjected to misuse, neglect, acts of God or
damage in transit.
Campbell Scientific will return guaranteed equipment by surface carrier
prepaid. Campbell Scientific will not reimburse the claimant for costs incurred
in removing and/or reinstalling equipment. This guarantee and the Company’s
obligation thereunder is in lieu of all other guarantees, expressed or implied,
including those of suitability and fitness for a particular purpose. Campbell
Scientific is not liable for consequential damage.
Please inform us before returning equipment and obtain a Repair Reference
Number whether the repair is under guarantee or not. Please state the faults as
clearly as possible, and if the product is out of the guarantee period it should
be accompanied by a purchase order. Quotations for repairs can be given on
request. It is the policy of Campbell Scientific to protect the health of its
employees and provide a safe working environment, in support of this policy a
“Declaration of Hazardous Material and Decontamination” form will be
issued for completion.
When returning equipment, the Repair Reference Number must be clearly
marked on the outside of the package. Complete the “Declaration of
Hazardous Material and Decontamination” form and ensure a completed copy
is returned with your goods. Please note your Repair may not be processed if
you do not include a copy of this form and Campbell Scientific Ltd reserves
the right to return goods at the customers’ expense.
Note that goods sent air freight are subject to Customs clearance fees which
Campbell Scientific will charge to customers. In many cases, these charges are
greater than the cost of the repair.
Campbell Scientific Ltd,
80 Hathern Road,
Shepshed, Loughborough, LE12 9GX, UK
Tel: [phone]
Fax: [phone]
Email: [e-mail]
www.campbellsci.co.uk

PLEASE READ FIRST
About this manual
Please note that this manual was originally produced by Campbell Scientific Inc. primarily for the North
American market. Some spellings, weights and measures may reflect this origin.
Some useful conversion factors:
Area: 1 in2(square inch) = 645 mm2
Length: 1 in. (inch) = 25.4 mm
1 ft (foot) = 304.8 mm
1 yard = 0.914 m
1 mile = 1.609 km
Mass: 1 oz. (ounce) = 28.35 g
1 lb (pound weight) = 0.454 kg
Pressure: 1 psi (lb/in2) = 68.95 mb
Volume: 1 UK pint = 568.3 ml
1 UK gallon = 4.546 litres
1 US gallon = 3.785 litres
In addition, while most of the information in the manual is correct for all countries, certain information
is specific to the North American market and so may not be applicable to European users.
Differences include the U.S standard external power supply details where some information (for
example the AC transformer input voltage) will not be applicable for British/European use. Please note,
however, that when a power supply adapter is ordered it will be suitable for use in your country.
Reference to some radio transmitters, digital cell phones and aerials may also not be applicable
according to your locality.
Some brackets, shields and enclosure options, including wiring, are not sold as standard items in the
European market; in some cases alternatives are offered. Details of the alternatives will be covered in
separate manuals.
Part numbers prefixed with a “#” symbol are special order parts for use with non-EU variants or for
special installations. Please quote the full part number with the # when ordering.
Recycling information
At the end of this product’s life it should not be put in commercial or domestic refuse but
sent for recycling. Any batteries contained within the product or used during the
products life should be removed from the product and also be sent to an appropriate
recycling facility.
Campbell Scientific Ltd can advise on the recycling of the equipment and in some cases
arrange collection and the correct disposal of it, although charges may apply for some
items or territories.
For further advice or support, please contact Campbell Scientific Ltd, or your local agent.
Campbell Scientific Ltd, 80 Hathern Road, Shepshed, Loughborough, LE12 9GX,
UK Tel: [phone] Fax: [phone]
Email: [e-mail]
www.campbellsci.co.uk

Safety
DANGER —MANY HAZARDS ARE ASSOCIATED WITH INSTALLING, USING, MAINTAINING, AND WORKING ON
OR AROUND TRIPODS, TOWERS, AND ANY ATTACHMENTS TO TRIPODS AND TOWERS SUCH AS SENSORS,
CROSSARMS, ENCLOSURES, ANTENNAS, ETC. FAILURE TO PROPERLY AND COMPLETELY ASSEMBLE,
INSTALL, OPERATE, USE, AND MAINTAIN TRIPODS, TOWERS, AND ATTACHMENTS, AND FAILURE TO HEED
WARNINGS, INCREASES THE RISK OF DEATH, ACCIDENT, SERIOUS INJURY, PROPERTY DAMAGE, AND
PRODUCT FAILURE. TAKE ALL REASONABLE PRECAUTIONS TO AVOID THESE HAZARDS. CHECK WITH YOUR
ORGANIZATION'S SAFETY COORDINATOR (OR POLICY) FOR PROCEDURES AND REQUIRED PROTECTIVE
EQUIPMENT PRIOR TO PERFORMING ANY WORK.
Use tripods, towers, and attachments to tripods and towers only for purposes for which they are designed. Do not
exceed design limits. Be familiar and comply with all instructions provided in product manuals. Manuals are
available at www.campbellsci.eu or by telephoning [phone] (UK). You are responsible for conformance
with governing codes and regulations, including safety regulations, and the integrity and location of structures or land
to which towers, tripods, and any attachments are attached. Installation sites should be evaluated and approved by a
qualified engineer. If questions or concerns arise regarding installation, use, or maintenance of tripods, towers,
attachments, or electrical connections, consult with a licensed and qualified engineer or electrician.
General
•Prior to performing site or installation work, obtain required approvals and permits. Comply with all
governing structure-height regulations, such as those of the FAA in the USA.
•Use only qualified personnel for installation, use, and maintenance of tripods and towers, and any
attachments to tripods and towers. The use of licensed and qualified contractors is highly recommended.
•Read all applicable instructions carefully and understand procedures thoroughly before beginning work.
•Wear a hardhat and eye protection, and take other appropriate safety precautions while working on or
around tripods and towers.
•Do not climb tripods or towers at any time, and prohibit climbing by other persons. Take reasonable
precautions to secure tripod and tower sites from trespassers.
•Use only manufacturer recommended parts, materials, and tools.
Utility and Electrical
•You can be killed or sustain serious bodily injury if the tripod, tower, or attachments you are installing,
constructing, using, or maintaining, or a tool, stake, or anchor, come in contact with overhead or
underground utility lines.
•Maintain a distance of at least one-and-one-half times structure height, or 20 feet, or the distance
required by applicable law, whichever is greater, between overhead utility lines and the structure (tripod,
tower, attachments, or tools).
•Prior to performing site or installation work, inform all utility companies and have all underground utilities
marked.
•Comply with all electrical codes. Electrical equipment and related grounding devices should be installed
by a licensed and qualified electrician.
Elevated Work and Weather
•Exercise extreme caution when performing elevated work.
•Use appropriate equipment and safety practices.
•During installation and maintenance, keep tower and tripod sites clear of un-trained or non-essential
personnel. Take precautions to prevent elevated tools and objects from dropping.
•Do not perform any work in inclement weather, including wind, rain, snow, lightning, etc.
Maintenance
•Periodically (at least yearly) check for wear and damage, including corrosion, stress cracks, frayed cables,
loose cable clamps, cable tightness, etc. and take necessary corrective actions.
•Periodically (at least yearly) check electrical ground connections.
WHILE EVERY ATTEMPT IS MADE TO EMBODY THE HIGHEST DEGREE OF SAFETY IN ALL CAMPBELL
SCIENTIFIC PRODUCTS, THE CUSTOMER ASSUMES ALL RISK FROM ANY INJURY RESULTING FROM IMPROPER
INSTALLATION, USE, OR MAINTENANCE OF TRIPODS, TOWERS, OR ATTACHMENTS TO TRIPODS AND TOWERS
SUCH AS SENSORS, CROSSARMS, ENCLOSURES, ANTENNAS, ETC.

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Table of Contents
PDF viewers: These page numbers refer to the printed version of this document. Use the
PDF reader bookmarks tab for links to specific sections.
1. Introduction................................................................ 1
2. Precautions................................................................ 1
3. Initial Inspection ........................................................ 2
4. Quickstart................................................................... 3
5. Overview .................................................................... 5
5.1 Power Considerations...........................................................................6
6. Specifications ............................................................ 7
6.1 Voltage Mode Output...........................................................................7
6.2 Current Mode Output ...........................................................................7
6.3 Isolation................................................................................................8
7. Installation ................................................................. 8
7.1 Connection to a Data Logger ...............................................................9
7.2 Output Device Connections ...............................................................10
7.2.1 Voltage Output Mode..................................................................11
7.2.2 Current Output Mode..................................................................11
7.2.3 Shield and Ground Connections..................................................12
7.2.4 Output Terminal Connectors.......................................................13
7.3 Output Mode Setting..........................................................................13
7.4 SDM Address Setting.........................................................................14
8. Operation ................................................................. 14
8.1 Voltage or Current Signaling .............................................................14
8.2 Providing Excitation Supplies to Sensors ..........................................15
8.3 Data Logger Programming.................................................................16
8.3.1 CRBasic SDMCVO4() Instruction .............................................16
8.3.2 SDMSpeed() Instruction .............................................................17
Appendices
A. Importing Short Cut Code Into CRBasic Editor... A-1
B. Example Program .................................................. B-1

Table of Contents
ii
Figures
7-1. Use of the Spring-Loaded Terminal Blocks (Top Position)...............10
7-2. Use of the Spring-Loaded Terminal Blocks (Front Position).............10
7-3. Closeup of Channel 4 Terminals........................................................10
7-4. Location of Jumpers on Circuit Board ...............................................13
7-5. Address Selection Switch...................................................................14
Tables
7-1. Data Logger to SDM-CVO4 Connections ...........................................9
7-2. Switch Position and Addresses ..........................................................14
9-1. Description of SDM Speed ................................................................17
CRBasic Example
B-1. CR1000X Program Using an SDM-CV04 to Output to a SCADA
System ..........................................................................................B-1

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SDM-CVO4 4-Channel Current/Voltage
Output Module
1. Introduction
The SDM-CVO4 is attached to a data logger and outputs variable voltage or
current signals under data logger program control. Typical applications include
driving remote current-loop display units, retransmitting measured values to
industrial control systems, sending control signals to valve controllers, and
providing excitation voltages or currents to external sensors.
This manual provides information only for CRBasic data loggers.
For retired Edlog data logger support, see an older manual at
www.campbellsci.com/old-manuals.
2. Precautions
The potential voltage difference between the data logger and the SDM-CVO4
outputs is considered to be non-hazardous (less than 50 V). Therefore, the
SDM-CVO4 is not a safety risk to the user.
As with the data logger, ensure that the device has a good connection to an
earth grounding point to allow the safe discharge of transient voltages and also
ensure proper screening of the device. The SDM-CVO4 has two Gterminals
on the black connector used for data logger connections. Use one of these
grounds to connect the device directly to the enclosure ground lug to ensure the
lowest resistance path to ground.
When the SDM-CVO4 is used in applications where the potential difference
between the data logger and the output terminals exceeds 50 V RMS AC,
74 VDC, careful consideration has to be taken to ensure safe operation and
compliance with local safety regulations. For such applications Campbell
Scientific does not supply the device as a stand-alone device which will meet
all safety requirements. The SDM-CVO4 is supplied as a component for the
user to install in a system that is, itself, designed to comply with such
regulations. The following guidance is given to help users meet the
requirements of such regulations.
The SDM-CVO4 is designed such that the internal safety barrier meets the
requirements of BS EN 61010-1 (similar to IEC 950). However, the method of
wire connection and earthing facilities prevents the unit being claimed as
compliant with such standards, when supplied as a stand-alone unit.
To meet the safety requirements of most countries, wires carrying hazardous
voltages, terminated in screw terminals must be housed in an enclosure
requiring a tool to open it, and the enclosure must have international symbols
on the outside warning of high voltages. An additional warning label, in the
local language, may be required stating that the source of hazardous voltage
must be turned off before the enclosure is opened.
NOTE

SDM-CVO4 4-Channel Current/Voltage Output Module
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Enclosures designed to house electrical equipment usually meet the standard
requirements. The ENC12/14, ENC14/16, and ENC16/18 enclosures meet these
requirements if fitted with a padlock and with the correct labels on the door.
Ensure that metal parts on the outside of the enclosure that might come in
contact with active high voltage circuits are connected to a safety ground. The
ground lug on Campbell Scientific enclosures is not an issue because it
normally is the point of contact to a good ground point.
Ensure that the cables and their connectors are rated to a high enough voltage
and assembled in a safe fashion. Provide adequate strain relief at the point of
exit from the enclosure.
If using an external device that has a high voltage, include a breaker system
that disconnects the device from the voltage source if the system insulation
breaks down.
With a system made to these requirements, the maximum recommended
continuous operating voltage between the data logger and input is 240 VAC.
This value is derived from the voltage rating of the terminal blocks used and an
internal suppression capacitor.
The unit is designed to withstand a transient flash test of 1500 V RMS AC, for
two seconds. However, the following design aspects can influence the test
results.
•To help suppress emissions of electromagnetic interference, the
isolation barrier is bridged by a 1nF, class ‘Y’ safety capacitor. This is
rated to withstand a 2700 V, 2 second flash test, but will fail if
exposed to voltages in excess of 240 V RMS for long periods.
•A spark gap protects the capacitor and opto-isolation component that
bridges the barrier from transients and static. The spark gap has a
2500 VDC nominal breakdown voltage. If this device is at the low
end of its tolerance band (±10%), combined with the normal tolerance
of flash test devices, the spark gap could fire during a 1500 VAC flash
test, which may cause an indication of failure. Testing at a slightly
lower voltage will confirm whether there is a true fault or not.
For questions about the safety of your installation, first seek advice from your
local safety advisor and then Campbell Scientific if you require further
technical details.
To ensure safe and correct operation, the SDM-CVO4 must
be installed where there is no risk of water ingress or
condensation.
3. Initial Inspection
Upon receipt of the SDM-CVO4, inspect the packaging and contents for
damage. File any damage claims with the shipping company. Immediately
check package contents against the shipping documentation. Contact Campbell
Scientific about any discrepancies.
CAUTION

SDM-CVO4 4-Channel Current/Voltage Output Module
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4. Quickstart
Avideo that describes data logger programming using Short Cut is available at:
www.campbellsci.eu/videos/cr1000x-datalogger-getting-started-program-
part-3.Short Cut is an easy way to program your data logger to measure the
sensor and assign data logger wiring terminals. Short Cut is available as a
download on www.campbellsci.eu.It is included in installations ofLoggerNet,
RTDAQ, PC400, or PC200W.
The following procedure shows using Short Cut to program the device.
1. Open Short Cut and click Create New Program.
2. Double-click the data logger model.
3. For each sensor, type the sensor model name in the Available Sensors
and Devices box, double-click the model name, set the Properties, and
wire the sensor to the data logger according to the Wiring tab. Refer to the
sensor manuals for more information.
4. In the Available Sensors and Devices box, type SDM-CVO4 or locate the
device in the Calculations > Control folder. Double-click Device for
Current/Voltage Input from SDM-CVO4. The SDM-CVO4 Address
defaults to 0. Type the correct SDM-CVO4 Address if it has been
changed from the factory default value. Select the Number of Outputs
and Output Range. For each measurement, click the Source
Measurement box and select the variable name, type the sensor-output
upper limit in the High Value for Engineering Units and the sensor-
output lower limit in the Low Value for Engineering Units. For example,
the wind speed output for the 03002 Wind Sensor is 0 to 50 m/s; therefore,
type 50 for the High Value for Engineering Units #1 and type 0 for the
Low Value for Engineering Units #1.

SDM-CVO4 4-Channel Current/Voltage Output Module
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5. Click the Wiring tab to see how the device is to be wired to the data
logger. Click OK after wiring the device.
6. In Output Setup, type the scan rate, meaningful table names, and Data
Output Storage Interval.

SDM-CVO4 4-Channel Current/Voltage Output Module
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7. Select the output options.
8. Click Finish and save the program. Send the program to the data logger if
the data logger is connected to the computer.
9. If the sensors are connected to the data logger, check the output of the
sensors in data display in LoggerNet, RTDAQ, PC400, or PC200W to
make sure it is making reasonable measurements.
5. Overview
The SDM-CVO4 includes four channels for connecting the external devices.
Each output can be set to 0 to 10 V or 0 to 20 mA by the data logger. The
output can be scaled and limited to 4 to 20 mA by the data logger program if
required by the application.
Typical applications include driving remote current-loop display units, re-
transmitting measured values to industrial control systems that have current or
high voltage inputs, sending control signals to valve controllers and providing
excitation voltages or currents to external sensors.
Each output is isolated both from the data logger and the other channels on the
SDM-CVO4, thereby avoiding ground loop problems that might otherwise
occur.
In the current mode, the output can either act as a 2-wire current controller,
where the loop is powered from a remote voltage source, or generate a 0 to
20 mA current source using a voltage output derived from its power supply.
The SDM-CVO4 is a synchronously addressed data logger peripheral. The data
logger SDM terminals are used to address the SDM-CVO4 and send data that
defines the desired voltage/current output of the four channels. The output
levels are set by four values stored in variables in the data logger. Up to sixteen
SDM-CVO4s or other SDM peripherals may be connected and addressed from
the same three terminals.
Features:
•Expands data logger current/voltage output capability

SDM-CVO4 4-Channel Current/Voltage Output Module
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•Provides four independent current or voltage outputs
•Drives remote current-loop display units
•Retransmits measured values to industrial control systems that have
current or high-voltage inputs
•Sends control signals to valve controllers
•Provides excitation voltages or currents to external sensors
•Compatible CRBasic data loggers: CR6, CR3000, CR1000X, CR800
series, CR1000
5.1 Power Considerations
The SDM-CVO4 power requirements are large compared to most Campbell
Scientific products, especially when driving significant loads. Care must be
taken to ensure that the power supply can cope with this higher demand.
Alkaline batteries are not recommended for long term applications.
The SDM-CVO4 has two internal power supplies, one for channels 1 and 2 and
one for channels 3 and 4. It only turns on the power supply for channels 3 and
4 if sent an instruction that sets the output of those channels. If channels 3 and
4 are not used, the power consumption is approximately 20 mA lower than
when all outputs are used.
Where supported by the data logger, and when the application allows it, the
SDM-CVO4 can be shut down to reduce its consumption to less than 0.5 mA.
In this state, all outputs are switched off.

SDM-CVO4 4-Channel Current/Voltage Output Module
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6. Specifications
Operating voltage: 12 VDC nominal (8 V to 16 V)
Current drain at 12 VDC: Typical active quiescent current 27 or 54 mA,
depending on operating mode (no load on output
ports). To estimate the total current, add the
quiescent current to the sum of all output currents
multiplied by 1.5.
For example, if each port is at 10 mA output, the
total = 54 + (1.5*4*10) = 114 mA. The device
can be shut down to <0.5 mA with all outputs off.
Maximum total
SDM cable length: 6 m (20 ft) if the SDMSpeed() CRBasic
instruction is not used. Longer cable lengths may
be acceptable if SDMSpeed() is used.
Operating temperature: –25 to 50 °C standard (–40 to 80 °C optional)
Size: 176 mm wide x 111 mm high x 24 mm deep
234 mm wide x 111 mm high x 24 mm deep
when fitted with brackets for mounting in
enclosure. Mounting brackets have two holes at
203.2 mm (8 in) spacing for screw fixings.
Weight: 370 g
EMC status: Complies with EN55022-1:1998 and
EN50082-1:1998
6.1 Voltage Mode Output
Range: 0 to 10,000 mV
Resolution: 2.5 mV
Maximum output current: 30 mA per channel
Minimum load current: 5 µA if output < 200 mV
Accuracy (23 °C): ±0.02% of set voltage + (±2.5 mV)
Accuracy (–25 to 50 °C): ±0.13% of set voltage + (±2.5 mV)
6.2 Current Mode Output
Range: 0 to 20 mA
Resolution: 5 µA
Minimum output
current (leakage): 5 µA at 50 °C
Accuracy (23 °C): ±0.02% of full scale range + (±5 µA).
Typical accuracy
(–25 to 50 °C): ±0.1% of full scale range + (±5 µA)
Worst case accuracy
(–25 to 50 °C): ±0.15% of full scale range + (±5 µA)

SDM-CVO4 4-Channel Current/Voltage Output Module
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Minimum voltage drop
across the internal current
regulating circuit: 2.5 V at 20 mA current flow
Maximum voltage into Id
relative to channel ground: 20 VDC
When in current mode, the Voterminal outputs
an unregulated voltage source at 15 V nominal
(±10%), 30 mA maximum load.
Please contact Campbell Scientific for the
accuracy specification on extended temperature
tested units.
6.3 Isolation
Design criteria: The unit has an internal isolation barrier and
components rated to provide signal isolation for
transients up to 1500 VAC (RMS), 2500 VDC
nominal. The isolation is between any output and
the SDM-CVO4 ground connection and between
individual output channels.
Protection components are built-in, which will
break down at voltages close to this limit (see
Section 2, Precautions (p. 1)).
Tested isolation: Each channel is tested for isolation resistance at
500 VDC. Pass level > 10 MΩ.
Maximum recommended
continuous operating
voltage: 240 VAC RMS differential between an output
and data logger ground - providing all issues
relating to local regulations for safe installation
and operation are followed (see Section 2,
Precautions (p. 1)).
7. Installation
Prior to installing the device, set the output mode (current or voltage) of each
channel by positioning internal jumpers (see Section 7.3, Output Mode Setting
(p. 13)). Also set the SDM address of the module (see Section 7.4, SDM Address
Setting (p. 14)) and consider safety issues specific to the installation (see Section
2, Precautions (p. 1)).

SDM-CVO4 4-Channel Current/Voltage Output Module
9
7.1 Connection to a Data Logger
For data logger connections, see TABLE 7-1.
TABLE 7-1. Data Logger to SDM-CVO4 Connections
Connection
Order SDM-CVO4 Data Logger Function
First +12 12 V on data logger or
external supply
Power
Second G
⏚
or G Common
Ground
C1 SDM-C1 (CR3000) or
C1 (other data loggers)
Data
C2 SDM-C2 (CRCR5000) or
C2 (other data loggers)
Clock
C3 SDM-C3 (CRCR5000) or
C3 (other data loggers)
Enable
Multiple SDM-CVO4s may be wired in parallel by connecting the SDM and
power connections from one SDM-CVO4 to the next.
The CR6 allows SDM operation through control terminals C1,
C2, and C3 as shown in TABLE 7-1. In addition, the Uterminals
on the CR6 may be used in the same manner. U1 to U3, U5 to U8,
and U9 to U11 are usable in the same Data, Clock, Enable order
as the Cterminals.
If the total cable length connecting SDM-CVO4s to
SDM-CVO4s, other SDMs and the data logger exceeds 6 m, the
SDM baud rate may need to be reduced to ensure reliable
operation. Please contact Campbell Scientific for more
information.
The transient protection of the SDM-CVO4 relies on a low resistance path to
earth. Ensure that the ground return wire has a low resistance. Connect the
SDM-CVO4 directly to the enclosure earth ground terminal.
Make sure the SDM-CVO4 ground wire connects to the data
logger Gterminal and not the ⏚(analogue ground) terminal.
The SDM-CVO4 uses spring-loaded terminal blocks to provide quick,
vibration resistant, connections. To attach wires, insert a small screwdriver into
either the top or front slot, as appropriate, and push to open the terminal spring.
Strip insulation from the wire to give 7 to 9 mm bare wire. Push the wire into
the opening, and, while holding it in position, withdraw the screwdriver to
release the spring. The wire will now be firmly held in place. See FIGURE 7-1
and FIGURE 7-2.
NOTE
NOTE
CAUTION

SDM-CVO4 4-Channel Current/Voltage Output Module
10
FIGURE 7-1. Use of the Spring-Loaded Terminal Blocks (Top Position)
FIGURE 7-2. Use of the Spring-Loaded Terminal Blocks (Front
Position)
Only insert one solid-core wire into one terminal unless the wires are soldered
or clamped together. When inserting more than one stranded wire, twist the
bare ends together before insertion.
7.2 Output Device Connections
Each output channel provides terminals labeled Vo, Id, and ⏚(FIGURE 7-3).
The two ⏚terminals are internally connected; two are provided for convenience.
FIGURE 7-3. Closeup of Channel 4 Terminals