Page 34 SMV800 Modbus User's Guide Revision 1.0
Background
You can set the LRV and URV for PT by either typing in the desired values on the MODBUS-
RTU host Process Temperature Config tab or applying the corresponding LRV and URV input
signals directly to the transmitter. The LRV and URV set the desired zero and span points for your
measurement range as shown the example in Figure 2-2.
Figure 2-2: RTD Range Configuration
• The URV changes automatically to compensate for any changes in the LRV and maintain
the present span (URV – LRV). See Figure 2-3 for an example.
• If you must change both the LRV and URV, always change the LRV first. However, if the
change in the LRV would cause the URV to exceed the URL, you would have to change
the URV to narrow the span before you could change the LRV
Figure 2-3: Current Range Settings
Damping
Adjust the damping time constant for Process Temperature to reduce the output noise. Default
value of damping is 0.5 seconds. Damping can be configured from 0 to 102 seconds.