Multi-Tech Systems 7500 User Manual

Page of 372
Configuring Analog Input
 ION 7500 / ION 7600 User’s Guide
Page 224
Digital and Analog I/O Technical Note
Configuring Analog Input
Analog inputs can measure and store analog information such as electrical signals 
from transducers; transducers derive the electrical signals from flow rates, 
temperatures, pressures, rotations, and fluid levels. Analog inputs require the 
installation of an optional circuit board inside the meter.
Analog Input Module
The Analog Input module takes an analog signal from a hardware port, scales it, 
and makes the scaled result available in its output register. 
ION meters with analog input connections have two types of analog input ports 
available when you order a meter (refer to your meter’s label to determine what 
type you ordered):
The accuracy of these analog inputs is ±0.3% of full-scale.
Connecting Auxiliary Analog Inputs (ION 7700 Meters)
The optional internal analog input boards for ION 7700 meters provide four 
double-ended current or voltage inputs for direct interface with transducers or 
thermocouples. The option ordered determines the configuration and maximum 
input range for all four analog input pairs (refer to the label on the ION 7700 for 
the AUX rating). All four must have the same input rating (e.g. 0 - 20 mA). Analog 
inputs receive DC signals only. Options include:
Analog Input Module Setup Registers
An ION Analog Input software module corresponds to each hardware input port. 
This module takes signals from an input port, scales it, and makes the result 
available to the meter. The register settings let you determine the value that 
appears in the output register when the lowest and highest possible values from 
the hardware are applied, and determine the hardware port that the module will 
control.
To learn more about the Analog Input module scaling, refer to the section “Setting 
Analog Zero and Full Scale Values” on page 227.
Analog Input Option
Input Impedance
Max Common Mode Voltage
0 to 1 mA
475 
Ω
8 V
0 to 20 mA (scalable to 4 - 20 mA)
25 
Ω
20 V
ION 7700 Analog Input Option
Input Impedance
Max Common Mode Voltage
0 to 1 mA
49.9 
Ω
8 V
0 to 20 mA
100 
Ω
20 V
0 to 1 V
>= 50 k
Ω
12 V
0 to 10 V
>= 50 k
Ω
25 V