Campbell Hausfeld SDM-CVO4 User Manual

SDM-CVO4

4-Channel Current/Voltage

Output Module

User Guide

Issued: 13.3.08

Copyright

Printed under Licence by Campbell Scientific Ltd.

2001-2007 Campbell Scientific Inc.

©

CSL 436

Guarantee

This equipment is guaranteed against defects in materials and
workmanship. This guarantee applies for twelve months from date of
delivery. We will repair or replace products which prove to be defective
during the guarantee period 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.

When returning equipment, the Repair Reference Number must be clearly
marked on the outside of the package.

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,

Campbell Park, 80 Hathern Road,

Shepshed, Loughborough, LE12 9GX, UK

Tel: [phone]

Fax: [phone]

Email: [e-mail]

www.campbellsci.co.uk

Contents

1. Introduction..................................................................1

2. Specifications..............................................................2

3. Power Considerations.................................................4

4. Installation....................................................................4

2.1 General Specifications..............................................................................2

2.2 Output Specifications................................................................................3

2.3 Isolation Specifications.............................................................................3

4.1 Connection to a Datalogger......................................................................4

4.2 Output Device Connections......................................................................6

4.2.1 Voltage Output Mode .....................................................................6

4.2.2 Current Output Mode......................................................................6

4.2.3 Shield and Ground Connections .....................................................8

4.2.4 Output Terminal Connectors...........................................................8

4.3 Output Mode Setting ................................................................................8

4.4 SDM Address Setting...............................................................................9

4.5 Safety Considerations.............................................................................10

5. General Principles of Use.........................................12

5.1 Voltage or Current Signalling.................................................................12

5.2 Providing Excitation Supplies to Sensors...............................................12

6. Datalogger Instruction (103).....................................13

6.1 Edlog Instruction 103 .............................................................................13

6.2 Edlog Program Examples.......................................................................15

6.2.1 Voltage and 0-20 mA Current Output Modes...............................15

6.2.2 Restricted Range Current Output Modes (4-20 mA)....................17

6.2.3 Providing Isolated Power Supplies to Sensor...............................18

6.3 CRBasic SDM-CVO4 Instruction ..........................................................20

6.4 SDM-CVO4 Instruction Example...........................................................21

Figures

1. SDM-CVO4................................................................................................1

4-1. Use of the Spring-Loaded Terminal Blocks (Top Position)....................5

4-2. Use of the Spring-Loaded Terminal Blocks (Front Position)..................5

4-3. Location of Jumpers on Circuit Board ....................................................9

4-4. Address Selection Switch......................................................................10

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Contents

Tables

4-1. Datalogger to SDM-CVO4 Connections.................................................4

4-2. Switch Position and Addresses .............................................................10

6-1. Description of Instruction 103 ..............................................................14

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SDM-CVO4 4-Channel Current/Voltage Output Module

The SDM-CVO4 is a synchronously addressed datalogger peripheral designed to allow the
datalogger to output variable voltage or current signals under program control.

Figure 1. SDM-CVO4 (shown without mounting brackets)

1. Introduction

The SDM-CVO4 expands the analogue output capability of Campbell Scientific
dataloggers. Each output can be set to 0-10V or 0-20mA by the datalogger. The
output can be scaled and limited to 4-20mA by the datalogger program if required
by the application.

Typical applications will include driving remote ‘current-loop’ display units, re­transmitting measured values to industrial control systems which 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 datalogger and the other channels on the
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 it can be used to generate a
0-20 mA current source using a voltage output derived from its own power
supply.

1

SDM-CVO4 4-Channel Current/Voltage Output Module

The SDM-CVO4 is a synchronously addressed datalogger peripheral. Datalogger
control ports 1, 2 and 3 are used to address the SDM-CVO4 and send out data that
defines the desired voltage/current output of each of the four channels. The output
levels are set by four values in successive input locations in the datalogger. A total
of up to sixteen SDM-CVO4s or other SDM peripherals may be connected and
addressed from the same three ‘SDM’ ports.

NOTE

For the CR10/10X, CR23X, CR7 and 21X dataloggers Instruction
103 is used to control the SDM-CVO4. This was introduced in
August 1988 for controlling SDM-AO4 functions. (The SDM-AO4
is an older voltage-output-only peripheral.) Dataloggers purchased
before this date may use a different instruction.

The SDM-CVO4 instruction is used with the CR800, CR1000,
CR3000, and CR5000.

2. Specifications

2.1 General Specifications

Compatible dataloggers: CR10X, CR800, CR1000, CR3000, CR5000, and

Operating voltage: 12 VDC nominal (8 V to 16 V)
Current drain at 12V DC: Typical active quiescent current 27 or 54 mA,

CR7. Also compatible with many retired
dataloggers such as the CR10, 21X, and CR23X.

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.

E.g. 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.

Operating temperature: -25°C 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, etc.
Mounting brackets have two holes at 203.2 mm (8")
spacing for screw fixings.

Weight: 370 g
EMC Status: Complies with EN55022-1:1998 and EN50082-

1:1998

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2.2 Output Specifications

Voltage Mode: Range: 0 – 10,000 mV

Accuracy (+23°C) ±0.02% of set voltage,

Accuracy (-25 to +50°C) ±0.13% of set voltage,

Current Mode: Range: 0 – 20 mA

Accuracy (+23°C) ±0.02% of full scale range,

Accuracy (-25 to +50°C) ±0.1% of full scale range,

Maximum voltage into I

When in current mode, the V

Instruction Manual

Resolution: 2.5 mV
Maximum Output Current: 30 mA per channel.
Minimum load current: 5 μA if output < 200 mV.

+ (± 2.5 mV).

+ (± 2.5 mV).

Resolution: 5 μA
Minimum output current (leakage): 5 μA at +50°C.

+ (± 5 μA).

+ (± 5 μA).
Minimum voltage drop across the internal current
regulating circuit: 2.5 V at 20 mA current flow.

relative to channel ground:

d

20 VDC.

terminal outputs an

o

unregulated voltage source at 15 V nominal (±10%),
30 mA max imum load.

Please contact Campbell Scientific for the accuracy

2.3 Isolation Specifications

Design criteria: The unit has an internal isolation barrier and

Protection components are built-in, which will break

Tested isolation: Each channel of each unit is tested for isolation

Maximum recommended continuous operating voltage:

specification on extended temperature tested units.

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.

down in a controlled fashion at voltages close to this
limit (see section 4.5, Safety Issues).

resistance at 500 VDC. Pass level > 10 MΩ.

240 VAC RMS differential between an output and
datalogger ground - providing all issues relating to
local regulations for safe installation and operation
are followed (see section 4.5, safety issues).

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