Allen-Bradley 1771-OW Contact Output Module
The 1771-OW controls eight relay contact outputs by sending the proper 8-bit data value to the module. The relay contacts can be set for either N.O. ( normally-open) or N.C. (normally-closed) configurations. The 1771-OW does not contain any surge limiting circuitry and is recommended to be used in resistive loads only, not inductive or capacitive loads. The contacts are rated at 24 - 138V AC rms, and 24 - 125V DC, 1A per channel. The minimum contact load is 10mA at 24V DC and 10mA at 24V AC.
1771-OW Contact Output Module Strapping
Remove the module's left hand cover plate (the one without the labels). Observe the location of the configuration jumpers in figure 10.1, and note the location of the individual channels. All outputs are individually selectable for either N.O. or N.C. operation. To select N.O. or N.C. settings refer to figure 10.1 for strap location and settings. K1 corresponds to signal 0 and K8 corresponds to signal 7. Note that figure 10.1 shows only the top four jumper points.
1771-OW Contact Output Module Installation
The Allen-Bradley 1771-OW Contact Output Module may be installed in any Allen-Bradley Universal I/O Chassis, 1771-A1B, 1771-A2B, 1771-A3B, or 1771-A4B. Before Installation, calculate the power requirements of the modules currently in the chassis. Add to that 700mA @ 5V DC, the current required by the 1771-OW. Check to be sure that this combined current requirement does not exceed the current driving ability of the chassis power supply.
Module Location in the I/O Chassis
The 1771-OW may be place in any slot of the I/O chassis with the exception of of the extreme left slot. This slot is occupied by the Remote I/O Adapter Module. It is suggested that analog input modules and low voltage DC modules be placed away from AC modules or high voltage DC modules to minimize electrical noise interference.
The Allen Bradley Universal I/O chassis have the ability to limit the slot access to certain modules by the implementation of a keying system. Modules are slotted in two places at the edge of the circuit board. The position of the keying bands on the backplane connector of the I/O chassis must correspond to these slots. To key a slot for use by the 1771-OW Contact Output only, place the keying bands between 6 and 8 and between 16 and 18 on the I/O chassis backplane connector.
Before a module is inserted into the Universal I/O Chassis, be sure that the power to the chassis is shut off. This can be done without shutting off the IOC that the Universal I/O Chassis is connected to, and without removing the subnet communication link. To insert the module, place it in the plastic tracks on the top and bottom of the Universal I/O Chassis. Slide the module into the Universal I/O Chassis until the module comes in contact with the backplane connector. Do not force the module in, instead apply firm and even pressure on the module to seat it properly on the backplane connector. Snap the chassis latch over the top of the module and connect the wiring arm to the module. The Universal I/O Chassis should begin communicating with the host IOC when power is reapplied, no rebooting of the IOC will have to be done.
1771-OW Contact Output Module Wiring Connection
Connecting field wiring to the 1771-OW is accomplished through the use of the wiring arm. Signals should be connected to the screw terminals on the wiring arm, as detailed in figure 10.2, and the wiring arm should be connected to the front tab connector on the 1771-OW. Note: The Contacts in figure 10.2show the factory default configuration. Each relay can be configured for either N.O. or N.C. operation. Refer to section 10.2 to properly configure each relay individually. When shielded cable is used and grounding of the shield is desired, it is recommended that the connection be made at one of the I/O chassis mounting bolts. To prevent ground loops only one end of the cable shield should be grounded.
1771-OW Contact Output Module Use
The front panel of the 1771-OW contains eight red LED indicators. Each indicator is lit when its corresponding relay is energized. The Top LED will indicate the status of signal 0, while the bottom LED will indicate the status of signal 7.