Model 175 Operations Manual - PR1008, Rev. 3
Capacitance Based Level Sensing of Common Industrial Fluids
Industrial Level Application Notes
Capacitance-based level sensing of Cryogenics
Cryogenic Level Application Notes
Simple Calibration
In contrast to competitor's systems in the industrial applications market, the Model 175 liquid level gauge provides simple microprocessor-controlled calibration. Simply press the MIN and MAX buttons to set the zero and span for any installed sensor. No tedious potentiometer adjustments are required for calibration. Calibration values are stored in non-volatile memory.
The Model 175 can effectively measure capacitance ranges from 15 to 100,000 pF. This is one of the largest ranges commercially available and is well suited for long probes in highly conductive fluids. A unique Auto-Ranging feature automatically chooses the minimum capacitance range that covers your signal span so that maximum accuracy is always achieved. This is all done automatically without the setting of jumpers, the need to know your media dielectric constant or time consuming recalibration.
ProxCalTM Advanced Calibration Feature
Although installed calibrations are always preferred, in many instances it may not be practical to perform a factory or field calibration in the target liquid. The advanced ProxCalTM feature allows the transmitter to be calibrated in a convenient similar liquid and then translate this calibration to the final target liquid. AMI commonly calibrates transmitter/probes in liquid nitrogen and then uses the ProxCalTM menu to enter in the dielectric value of the new fluid and save the calibration for applications such as Hydrogen or Oxygen. This feature is especially useful when the installed conditions will be at extremely high pressures because it lets the unit begin functioning right out of the box.
Don't know the dielectric value of your target fluid? No Problem! Another unique and very useful way to use ProxCalTM is to install a calibrated transmitter/probe into a new vessel containing the target liquid. If the level at that time is known by some other method (manual gauge, tape & float manual strapping measurement, etc.) then the I&E Tech can simply adjust the ProxCalTM value until the level reading matches the level in the tank - All Done! This means a simple factory water calibration provides everything you need to easily field calibrate the unit upon installation in acids, bases, slurries, etc.
Remote Monitoring - Easy Installation - Simple Serviceability
The Model 175 level gauge comes with a 4-20 mA output which corresponds to 0-100% liquid level.
The electronics "puck" shown to right is field replaceable and requires no rewiring. All of the field wiring is installed into a stationary base ring inside the enclosure. This configuration also provides plenty of room for initial field wiring without the transmitter electronics being in the way during installation.
Mounting Options
The level transmitter housing can be mounted directly to the top of the probe (integral mount) or remotely mounted up to 10 ft. away (remote mount). A simple high quality remote mount kit includes a stainless steel bracket with threaded nipple welded in place, stainless steel U-bolts and a remote interconnect enclosure that attaches to the top of the level probe. The signal coax between the electronics and probe is routed through standard industrial conduit provided by the customer.
Agency Approvals
The Model 175 level measurement system comes standard with CE approval. If your application requires Factory Mutual (FM) approved Explosion-Proof, Intrinsically Safe or Non-Incendive. Our Model 32E has these approvals.
Existing Cap Probe Compatibility
The Model 175 can quickly and easily act as a drop in replacement to work with existing capacitance probes made by other manufacturers. Doing so upgrades your system without the need for vessel entry or the purchase of a new probe. Has I&E isolated your problem to a faulty or problematic signal conditioning unit or transmitter? Upgrade with a state of the art Model 175 and re-use your existing probe. Is your process down? We can normally ship a retrofit transmitter within 1 day. Retrofitting an existing probe is also a great way to try out our unit for the first time.
