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USER GUIDE
SCC-CO20 Isolated Current
Output Module
The SCC-CO20 is an isolated current output module that outputs up to
20 mA. The output current level is proportional to the voltage applied to
the module by an analog output channel of an E/M Series DAQ device.
Conventions
The following conventions are used in this guide:
<> Angle brackets that contain numbers separated by an ellipsis represent
a range of values associated with a bit or signal name—for example,
AO <3..0>.
» The » symbol lea
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italic Italic text denotes variables, emphasis, a cross-reference, or an introduction to a key concept. Italic text also denotes text that is a placeholder for a word or value that you must supply. monospace Text in this font denotes text or characters that you should enter from the keyboard, sections of code, programming examples, and syntax examples. This font is also used for the proper names of disk drives, paths, directories, programs, subprograms, subroutines, device names, functions,
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❑ Tools – 1/8 in. flathead screwdriver – Numbers 1 and 2 Phillips screwdrivers – Wire insulation stripper Note Software scaling of measurements is not supported on the Macintosh operating system. Refer to the SCC-CO20 Module Pin Assignments section. You can download NI documents from ni.com/manuals. To download the latest version of NI-DAQmx, click Download Software atni.com. Device Specific Information Note For general SCC module installation and signal connection information, and informatio
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E/M Series DAQ Device SCC-CO20 3 15 V iso 2 AO (X ) AO GND 1 I Figure 1. SCC-CO20 Signal Connections to E/M Series DAQ Device Using the Isolated Loop Supply of the SCC-CO20 You can connect the SCC-CO20 to a load using either the isolated internal loop supply or an external supply. The internal loop supply outputs a voltage of 15 V with respect to the isolated ground reference. When using the internal loop supply, the compliance voltage is 12.5 V. This allows for a maximum load resistance of
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Note If your load is grounded and you are using the internal supply, connect the load ground to the current sink terminal at pin 2 on the SCC-CO20. Do not connect the load ground to the isolated ground terminal because doing so could defeat the module isolation. Driving Higher-Resistance Loads with the SCC-CO20 In order to calculate the supply voltage your application requires, multiply the load resistance by the current you need to sink, then add 2.5 V for the voltage drop across the protec
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SCC-CO20 3 SUPPLY 15 V iso 2 1 ISO GND I SCC-CO20 3 SUPPLY 15 V iso Load 2 SINK 1 I Figure 3. Connecting Two SCC-CO20 Modules to a Higher-Resistance Load SCC-CO20 Isolated Current Output Module User Guide 6 ni.com – + – +
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Using an External Loop Supply In order for the current sink to operate properly with an external loop supply, the voltage must be within the range of 3 to 42 V. If the voltage is too high, overheating can occur and damage the module. Figure 4 shows four configurations using an external loop supply. SCC-CO20 SCC-CO20 2 SINK 2 SINK Load 0–20 mA 0–20 mA Load 1 1 ISO GND ISO GND I I a. Nonreferenced load and external voltage supply (two circuits) SCC-CO20 SCC-CO20 2 SINK 2 SINK Load 0
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SCC-CO20 2 SINK 0–20 mA 1 ISO GND Load I Figure 5. Connecting the SCC-CO20 to a Grounded External Loop Supply and a Grounded Load For information about how to configure the SCC-CO20 module using NI-DAQmx, refer to the SCC Quick Start Guide. Calibrating Gain and Offset Errors The SCC-CO20 is calibrated at the factory before shipment. If you want to adjust the gain and offset of the SCC-CO20 in your system using an E/M Series DAQ device, you need a current meter (ammeter) with an ac
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Note Normally you would adjust to 0 μA in order to calibrate the offset, but because the SCC-CO20 cannot source current, it is impossible to know when you have adjusted past 0 μA. Using the SCC-CO20 The SCC-CO20 is a 0 to 20 mA programmable current sink. The current output is controlled by AO (X), a 0 to 10 V unipolar DAC output channel of an E/M Series DAQ device. The relationship between the AO (X) voltage level and the current output of the SCC-CO20 is linear and is described by the fol
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Specifications These ratings are typical at 25 °C unless otherwise stated. Electrical Number of output channels.....................1 Output referencing..................................Nonreferenced (floating) Input range..............................................0 to 10 V Output range ...........................................0 to 20 mA Voltage compliance ................................12.5 V Maximum load resistance 5 mA ................................................2,500 Ω 10 mA ......
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Physical 1.87 cm (0.74 in.) 7.93 cm (3.12 in.) 3.55 cm (1.4 in.) Figure 6. SCC-CO20 Dimensions Weight.................................................... 28 g (1.0 oz) I/O connectors ........................................ One 20-pin right-angle male connector One 3-pin screw terminal Field-wiring diameter............................. 28 to 16 AWG Maximum Working Voltage (Signal + common-mode) each input should remain within 42.4 V or peak 60 VDC of ground. Maximum working voltage refe
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Environmental Operating temperature ............................0 to 50 °C Storage temperature................................–20 to 70 °C Humidity.................................................10 to 90% RH, noncondensing Maximum altitude...................................2,000 m Pollution Degree (indoor use only) ........2 Safety This product meets the requirements of the following standards of safety for electrical equipment for measurement, control, and laboratory use: � IEC 61010-1, EN 61
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Online Product Certification Refer to the product Declaration of Conformity (DoC) for additional regulatory compliance information. To obtain product certifications and the DoC for this product, visit ni.com/certification, search by model number or product line, and click the appropriate link in the Certification column. Environmental Management NI is committed to designing and manufacturing products in an environmentally responsible manner. NI recognizes that eliminating certain hazardou
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SCC-CO20 Module Pin Assignments Figure 7 shows the I/O connector pins on the bottom of the module. 4 1 2 5 3 1Pin 1 2Pin 2 3 PWB Key 4 Pin 19 5Pin 20 Figure 7. SCC-CO20 Bottom View Table 1 lists the signal connection corresponding to each pin. Table 1. SCC-CO20 Pin Signal Connections Pin Number Signal 1 E/M Series AO (X) 2 E/M Series AO GND 3 — 4 E/M Series AO GND 5 — 6 — 7 — 8 — 9 +5 V 10 GND 11 — 12 +5 V REF 13 +15 V SCC-CO20 Isolated Current Output Module User Guide 14 ni.com
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Table 1. SCC-CO20 Pin Signal Connections (Continued) Pin Number Signal 14 –15 V 15 — 16 — 17 — 18 — 19 — 20 — National Instruments, NI, ni.com, and LabVIEW are trademarks of National Instruments Corporation. Refer to the Terms of Use section on ni.com/legal for more information about National Instruments trademarks. Other product and company names mentioned herein are trademarks or trade names of their respective companies. For patents covering National Instruments products/technology, re
