Allen-Bradley 1756-OB16IS User Manual

Rockwell Automation Publication 1756-UM058G-EN-P - November 2012 73
Diagnostic Module Features Chapter 4
Open Wire Detection
Open Wire is used to verify the field wiring is connected to the module. The field
device must provide a minimum leakage current to function properly.
A leakage resistor must be placed across the contacts of an input device. The
resulting current is then expected to exist when the input is open. For more
information, see each module’s specifications in Chapter
8.
When an Open Wire condition is detected, a point-level fault is sent to the
controller to identify the exact point fault. This feature has a corresponding tag
that can be examined in the user program in the event of a fault.
Follow these steps to configure open wire detection.
1. On the Module Properties dialog box, click the Configuration tab.
2. Do one of the following in the Open Wire (middle) column:
• To enable the open wire detection for a specific point, check the
corresponding checkbox.
• To disable open wire detection for a specific point, clear the
corresponding checkbox.
3. Click OK.

Allen-Bradley 1756-OB16IS Specifications

General

Manufacturer	Allen-Bradley
Product Type	Digital Output Module
Series	1756
Number of Outputs	16
Output Type	Sourcing
Voltage Category	24V DC
Output Current	0.5 A per point, 8 A per module
Operating Voltage	19.2V DC to 30V DC
Module Location	ControlLogix Chassis
Operating Temperature	0 to 60 °C (32 to 140 °F)
Connection Type	Removable Terminal Block
Compatibility	ControlLogix
Temperature Rating	0°C to 60°C
Voltage Rating	10…30V DC
Intrinsic Safety	Yes, for hazardous locations (Class I, Division 2, Groups A, B, C, D)