A customer needed to re-range a Siemens SITRANS P DS III transmitter without applying pressure. He’d read my earlier blog post about using the pushbuttons to program the DS III (Pressure Transmitter Pushbuttons to the Rescue!), and where to find the Z-fold instruction sheet.
All was going to plan, until he started looking for the settings for lower range value (LRV) and upper range value (URV). And then, in an all-too-familiar scenario, he hit a roadblock. The instructions don’t actually mention URV and LRV, the terms he’s familiar with, by name or acronym. So what’s a guy to do?
On page 6 of the Z-fold instructions, there are a list of Mode codes that correspond to the settings he needed.
The Siemens mode codes for ranging a transmitter without applying pressure are:
- M5: Adjust MA without pressure
Sets transmitter lower range value (LRV). Siemens uses MA to denote start of scale, or bottom of range.
- M6: Adjust ME without pressure
Sets transmitter upper range value (URV). Siemens uses ME to denote full scale or top of range.
The Up and Down arrow pushbuttons adjust the value. The M pushbutton saves the value once you have it set to your required parameter.
Ranging pressure in level applications
M2: Set and adjust MA and M3: Set and adjust ME are for what I call ‘wet’ ranging, using for ranging the pressure transmitters in level applications.
Apply a pressure corresponding to a low level (4.0 mA), and M2 will use that for the lower range value. Apply the pressure corresponding to the high level (20.0 mA), and M3 uses that for the high level range value.
The zero trim adjustment is aptly called M7 Zero adjustment. Zero trim is typically done on low pressure range transmitters to compensate for any zero offset due to installation factors, like out-of-plumb, elevation offset or not level. You’ll use the pushbutton Up and Down arrows to bring the reading to zero (when the applied pressure is at zero). The M button locks in that offset as the 4.000mA point.
Check Lesman.com for complete specifications and user manuals on the Siemens SITRANS P DS III transmitter.
Lesman Instrument Company is the authorized Siemens representative in Illinois, Indiana, Missouri, Paducah KY, Wisconsin, and Michigan’s Upper Peninsula. If you are located outside that area, you can find your local sales office or get technical assistance by calling 800-365-8766.