Westermo RM-115S - Manual (Page 32)

115S Serial I/O Module User Manual
Page 32 June 2011
4.4.1.2 Differential voltage input
The 115S-12 can be configured to measure differential voltage. Neighbouring channels
serve as reference voltages in this mode. The four differential pairs are: AIN1-AIN2,
AIN3-AIN4, AIN5-AIN6, and AIN7-AIN8.
Note: If mapping Differential Voltage inputs using the Elpro E-Series Configuration
software only map the Odd inputs.
E.g. AIN1 for the first Differential input, AIN3 for the second, AIN5 for the third
and AIN7 for the fourth.
If using Modbus all registers can be read but only the odd registers holds the values,
i.e. 30001 for AIN1-AIN2, 30003 for AIN3-AIN4, 30005 for AIN5- AIN6 and 30007
for AIN7-AIN8.
Choose the page to configure the 115S-12 for differential voltage input, as shown in
Figure 4-6.
Remove the access panel from the front of the 115S-12 case to gain access
to the dip switches. Replace the access panel after setting the switches.
Set the switches according to the picture shown. The unit should be orientated with the
20-way connector towards you.
Figure 4-6: Setup page for differential voltage input.