Inverting your plant signals
Ian Loudon
4 to 20mA in represents 20 to 4mA out?
Many analogue control applications require reverse action with respect to traditional plant instrumentation signals. e.g. 4 to 20mA in and 20 to 4mA out. Many control or safety systems use this technique. Interfacing to these devices on an analogue level can be difficult and indeed many specialized devices have been employed in this role. Using Omniterm TxB this application has been reduced to simplicity itself. Any signal input and be represented inverted at the output not just 4-20mA. This facility is just one of the many standard features on the TxB, so it's still the same stock item you would use for temperature signal conditioning - no extra inventory! Try it out for yourself.
Isolation for Plant and Personnel Safety
Most Plant devices require interface signals to or from them and many have dangerous voltage levels for example variable speed drives which could easily be floating at several hundred volts relative to ground. Without isolation on these interfaces plant and personnel are exposed. The Omniterm Signal Isolators ensure trouble free installations and safety of plant personnel who can inadvertantly come into contact with these signals in other areas of the plant where there is no apparent indication of danger.
Omniterm Universal Special Function Module
Latest Release - The Omniterm Universal Special Function Module TFX
The OMNITERM TFX Special Function Module is ideal for those special applications where mathematical computations are required on your analogue signals. The TFX accepts two 1-5V or 4-20mA inputs and provides one universal output. The Omniterm TFX comes equipped with a wide selection of common mathematical functions. A user configurable 32 point linearisation table enables TxB to solve a wide range of signal processing applications such as belt slip monitoring, dual-redundant analogue inputs, ratio monitoring, rate-of-change monitoring etc.
Select from a wide range of computation functions Fully configurable by the user Accepts two 4-20mA or 1-5Vdc inputs One universal 0-20mA / 0 to +-10V / 0 to +-10mA or Output isolation to 1500Vac
Solutions for:
- Integration (Pulse Output)
- Square Root Integration
- Hi/Lo Follower
- Multiply/Divide or Ratio
- Deviation Monitoring - Absolute Value
- Average Value
- Linearisation (Square Root, Log 10, Ln, Sin, Cos Standard)
- Rate Function - Ramp Limiter and Rate of change.
- Track Functions - Track and Hold, Peak and Valley.
Last Month:
Last month we talked about several important topics including:
- Inverting your plant signals
- Isolation for Plant and Personnel Safety
- Omniterm Universal Special Function Module
If you missed these or other key discussions,
you can find the back issues on the newsletters
page of our website:
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