Allen-Bradley 1771-IXE Thermocouple / Millivolt Input Module
The 1771-IXE senses up to 8 differential analog inputs and converts them to a proportional 12 bit binary value. The 1771-IXE will support E, J, K, T, R, and S thermocouples, as will as a range of +/- 100mV. These ranges are selectable in the EPICS database configuration software.
1771-IXE Thermocouple / Millivolt Input Module Strapping
No strapping of the 1771-IXE Module is required.
1771-IXE Thermocouple / Millivolt Input Module Installation
The Allen-Bradley 1771-IXE Analog Input 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 1.2A @ 5V DC, the current required by the 1771-IFE. 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-IFE 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-IFE Analog Input only, place the keying bands between 20 and 22 and between 24 and 26 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-IXE Thermocouple / Millivolt Input Module Wiring Connection
Connection of analog signals to the 1771-IXE 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 13.1, and the wiring arm should be connected to the front tab connector on the 1771-IXE. The recommend maximum cable length for thermocouple signals is 1000ft for thermocouple extension wire of 18 or 22 gauge. This is based on the fact that the 1771-IXE module compensates for lead resistance up to 2000 ohms. If this lead resistance must be exceeded, refer to the thermocouple manufacturer's specifications and instructions for compensation. 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. Note also that all unused inputs should be short circuited.
1771-IXE Thermocouple / Millivolt Input Module Use
The front panel of the 1771-IFE contains a green RUN and a red FAULT LED indicator. At power up an initial module self-check occurs. If there is no fault the red indicator will turn off. The green indicator will flash until the processor communicates successfully with the module.