NI CFP-CB-1 Compact FieldPoint Connector Blocks

NI CFP-CB-1 Compact FieldPoint Connector Blocks

Features

The cFP-CB-1 and cFP-CB-3 are Compact FieldPoint connector blocks with the following features:

• cFP-CB-1 is designed for general-purpose and hazardous voltage1 operation with all Compact FieldPoint I/O modules 

• Isothermal construction of cFP-CB-3 minimizes temperature gradients for use with thermocouples 

• Mount on a cFP-BP-x Compact FieldPoint backplane 

• 36 terminals available (cFP-CB-3 has 18) 

• Tie-wrap anchors for wires 

• Color-coded V and C terminals for voltage supply and common connections 

• –40 to 70 °C operation

Minimizing Thermal Gradients

To minimize the thermal gradient across the terminals, use the cFP-CB-3 for connecting thermocouple signals. The cFP-CB-3 is designed with isothermal construction to keep the terminals at the same temperature. In addition to using the cFP-CB-3, you can minimize thermal gradients by following these guidelines:

• Do not place power supplies or other heat sources directly above or below the Compact FieldPoint system. 

• Do not install high-power modules, such as the cFP-DO-4xx and cFP-RLY-4xx, adjacent to the cFP-CB-3. 

• Use small-gauge thermocouple wire to transfer less heat. 

• Run thermocouple wires together near the connector block to keep them at the same temperature. 

• Avoid running thermocouple wires near hot or cold objects. 

• Use the foam cushion strain relief to restrict air flow.

Isolation and Safety Guidelines

This section describes the isolation of the cFP-CB-x and its compliance with international safety standards. The field wiring connections are isolated from the backplane and the inter-module communication bus. The isolation is provided by the module, which has optical and galvanic isolation barriers designed and tested to protect against transient fault voltages of up to 2,300 Vrms. The cFP-CB-x provides double insulation (compliant with IEC 61010-1) for working voltages of 250 Vrms1. Safety standards (such as those published by UL and IEC) require the use of double insulation between hazardous voltages and any human-accessible parts or circuits.

Never try to use any isolation product between human-accessible parts (such as DIN rails or monitoring stations) and circuits that can be at hazardous potentials under normal conditions, unless the product is specifically designed for such an application as is the cFP-CB-x.

Even though the cFP-CB-x is designed to handle applications with hazardous potentials, follow these guidelines to ensure a safe total system:

• The cFP-CB-x has a safety isolation barrier between the I/O channels and the inter-module communication bus. There is no isolation between channels unless otherwise noted. If any of the channels on a module are wired at a hazardous potential, make sure that all other devices or circuits connected to that module are properly insulated from human contact. 

• Do not share the external supply voltages (the V and C terminals) with other devices (including other FieldPoint devices), unless those devices are isolated from human contact. • You must connect the protective earth (PE) ground terminal on the cFP-BP-x backplane to the system safety ground. The backplane PE ground terminal has the following symbol stamped beside it: . Connect the backplane PE ground terminal to the system safety ground using 14 AWG (1.6 mm) wire with a ring lug. Use the 5/16 in. panhead screw shipped with the backplane to secure the ring lug to the backplane PE ground terminal. 

• As with any hazardous voltage wiring, make sure that all wiring and connections meet applicable electrical codes and commonsense practices. Mount the backplane in an area, position, or cabinet that prevents accidental or unauthorized access to wiring that carries hazardous voltages. 

• The isolation of the cFP-CB-x is certified as double-insulated for working voltages of 250 Vrms. Do not use the cFP-CB-x as the only isolating barrier between human contact and working voltages of more than 250 Vrms. 

• Operate the cFP-CB-x only at or below Pollution Degree 2. Pollution Degree 2 means that only nonconductive pollution occurs in most cases. Occasionally, however, a temporary conductivity caused by condensation must be expected.

• Do not operate FieldPoint products in an explosive atmosphere or where there may be flammable gases or fumes. If you need to operate FieldPoint products in such an environment, the FieldPoint products must be in a suitably rated enclosure. 

• Operate the cFP-CB-x at or below Installation Category II. Installation Category II is for measurements performed on circuits directly connected to the electrical distribution system. This category refers to local-level distribution, such as that provided by a standard wall outlet.