Campbell SDM-CD16D User manual

SDM-CD16D
16 Channel Digital Control
Port Expansion Module
User Guide
Issued 15.6.99
Copyright 1999 Campbell Scientific Ltd.

Guarantee
This equipment is guaranteed against defects in materials, workmanship,
and software. 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 Refer-
ence 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 re-
pairs 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, Leicestershire, LE12 9RP, UK
Tel: [phone]
Fax: [phone]
Email: [email protected]
www.campbellsci.co.uk

Contents
1. Introduction...................................................................1
2. Control Specifications..................................................1
2.1 General................................................................................................1
2.2 Output Specifications...........................................................................2
3. Power Considerations..................................................2
4. Installation.....................................................................3
4.1 Controlled Device Connections............................................................4
5. Address Selection Switches........................................5
6. Datalogger Instructions 104 (CR10/10X, CR23X,
21X & newer CR7s) and 29 (older CR7s)...................6
7. Theory of Operation......................................................7
8. Program Example..........................................................7
Figures
1. SDM-CD16D.........................................................................................1
2. Equivalent Output Driver Circuit...........................................................2
3. Connection Block Diagrams...................................................................3
4. Use of Terminal Blocks..........................................................................5
5. Address Selection Switch.......................................................................6
Tables
1. Datalogger to SDM-CD16D Connections...............................................4
2. Switch Position and Address..................................................................5

1
SDM-CD16D 16 Channel Digital Control
Port Expansion Module
The SDM-CD16D (see Figure 1) is a synchronously addressed peripheral. It has 16 control
ports and is compatible with Campbell Scientific’s CR10/10X, CR23X, CR7 and 21X
dataloggers.
Figure 1 SDM-CD16D
1. Introduction
The SDM-CD16D expands the digital output capability of Campbell Scientific
dataloggers. The outputs can be set to 0 or 5V by the datalogger. In addition to
being able to drive normal logic level inputs, when an output is set HI a ‘boost’
circuit allows it to source a current of up to 100mA, allowing direct control of low
voltage valves, relays etc.
The SDM-CD16D is a synchronously addressed datalogger peripheral. Datalogger
control ports 1, 2 and 3 are used to address the SDM-CD16D then clock out the
desired state of each of the 16 control ports. Up to sixteen SDM-CD16Ds may be
addressed, making it possible to control a maximum of 256 ports from the first
three datalogger control ports.
CR10/10X, CR23X, CR7 and 21X dataloggers use I/O Instruction
104 to control the SDM-CD16D.
Older dataloggers with pre-OS7.1 software may not have the
necessary instruction, or may use Instruction 29. Ensure that your
datalogger contains the appropriate instruction before using.
2. Control Specifications
2.1 General
Compatible dataloggers: CR10/10X, CR23X, CR7 and 21X
Operating voltage: 12V DC nominal (9 to 18V)
Current drain at 12V DC: 100µA typical (All ports HI, no load)
Total cable length: 6m (CR10/10X, CR23X, 21X), 180m (CR7)
NOTE

SDM-CD16D 16 Channel Digital Control Port Expansion Module
2
2.2 Output Specifications
Output Voltage (no load): Output ON/HI, Nominal 5V (Minimum 4.5V)
Output OFF/LO, Nominal 0V (Maximum 0.1V)
Output Sink Current: Output will sink 8.6mA from a 5V source*
Output Source Current: Output will source 36mA @ 3V,
115mA short-circuited to ground*
Max. Output Current: 400mA at 50°C and 12V supply (see NOTE below)
(total all outputs)
The maximum current should be derated under the following
conditions:
50mA for every 10°C above 50°C and/or 50mA for every volt
above 12V.
Operating temp.: -25°C to +70°C standard
Size: 230mm wide x 100mm high x 24mm deep
Weight: 350g
EMC Status: Complies with EN55022-1:1998 and
EN50082-1:1998
* If more detailed output characteristics are required, experienced users should consult the
equivalent circuit diagrams shown in Figure 2, below.
Figure 2 Equivalent Output Driver Circuit
3. Power Considerations
The SDM-CD16D power requirements are large compared to most Campbell
Scientific products when driving significant loads. For many applications an
external power supply, as shown in Figure 3, is recommended to power the
SDM-CD16D.
For some applications it may be convenient to use the datalogger supply to power
the SDM-CD16D, as shown in Figure 3. For long-term applications, the lead-acid
power supply available with Campbell Scientific dataloggers should be used,
allowing the batteries to be float charged. Alkaline batteries are not recommended
for long term applications.
NOTE
0.6V Drop
Output
Output
580R
Output set ON/HI Output set OFF/LO
5
1
0
R
39
R
V
5V, 0Ω

User Guide
3
Connection with External Supply
Connection with Datalogger Supply
Figure 3 Connection Block Diagrams
If the 21X power supply is used to power the SDM-CD16D, all low
level analogue measurements (thermocouples, pyranometers,
thermopiles, etc.) must be made differentially.This is a result of slight
ground potentials created along the 21X analogue terminal strip when
the 12V supply is used to power peripherals. This limitation reduces
the number of available analogue input channels and may make an
external supply for the SDM-CD16D essential.
4. Installation
For correct operation the SDM-CD16D must be installed where there is no
risk of water ingress or condensation.
The order in which connections are made is critical.
Always
connect 12V first
, followed by ground, then the control ports.
For datalogger connections, see Table 1, below. Please refer to Figure 4 for details
of how to use the spring-loaded terminals.
NOTE
CAUTION
GND
EXTERNAL
9 TO 18V DC
+ –
SDM-CD16D DATALOGGER
12V C1
C2
C3
SDM-CD16D DATALOGGER
GND
12V
C1
C2
C3

SDM-CD16D 16 Channel Digital Control Port Expansion Module
4
Table 1 Datalogger to SDM-CD16D Connections
Connection Order SDM-CD16D Datalogger Function
First 12V 12V on datalogger or
external supply
Power
Second
C1
C2
C3
or G
C1 (Control Port 1)
C2 (Control Port 2)
C3 (Control Port 3)
Common Ground
Data
Clock
Enable
Multiple SDM-CD16Ds may be wired in parallel by connecting the datalogger
side of one SDM-CD16D to the next.
The transient protection of the SDM-CD16D relies on a low resistance path
to earth. Ensure that the ground return wire has as low a resistance as
possible. Where long cable runs are likely, or where lightning damage is a
possibility, the SDM-CD16D can be fitted with gas discharge tubes. Please
contact Campbell Scientific for details.
For CR10/10X, CR23X and 21X dataloggers, the total cable length
connecting SDM-CD16Ds to SDM-CD16Ds and the datalogger
should not exceed 6m. Total cable lengths in excess of 6m will
adversely affect communication performance. For CR7 dataloggers,
the total cable length can be up to 180m.
4.1 Controlled Device Connections
The SDM-CD16D uses spring-loaded terminal blocks, which provide quick,
vibration resistant, connections. The output terminals are labelled 1 to 16. A
common ground connector is provided between each pair of terminals
Use a screwdriver in either the top or front slot, as appropriate, to open the
terminal spring. Strip any insulation from the wire to give 7 to 9mm 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 4, below.
You cannot reliably insert more than one solid-core wire into one
terminal connector unless the wires are soldered or clamped
together. When inserting more than one stranded wire, twist the bare
ends together before insertion.
NOTE
NOTE