Measurement Computing PointScan 200 Series rev.1.0 - Manual (Page 33)

PointScan/200 User’s Manual 9-25-01 Combination I/O Modules 8-3
Wiring
A pair of floating terminals is provided for each discrete input to provide channel-to-channel isolation and a
choice of sourcing (power switching), sinking (ground switching) or AC signals on each input. Two
terminals are provided for each analog input channel. Either DC power or ground may be provided for each
input device by setting a jumper inside the base. (Access these jumpers by unplugging the module and then
opening the hinged door in the wiring base.) Refer to the diagram below. Please be sure to provide a
suitable instrumentation ground to avoid measurement errors due to ground loops.
Current Shunts
Precision 100 ohm current shunts, beneath the hinged access door in the wiring base, pass current and
maintain loop integrity for each of the four analog input channels even if the module is unplugged. A spare
shunt is provided and may be simply inserted in place of any socketed shunt that open circuits as a result of
a current overload.
I/O Registers
Function IOtech Registers Modbus Registers
Discrete Inputs X0 - X3 10001 - 10004
Analog Inputs AX0 - AX3 30001 - 30004 Bipolar values: -32768
Æ 32767
Counter Inputs AX4 - AX7 30005 - 30008 Unsigned values: 0
Æ 65,535