Portable instruments have evolved through several iterations to encompass as much data collection, analytical, and correction tools as possible in a single, convenient, and light-weight package. No matter what, walking (or crawling) from one production machine point to another it is still a dangerous and uncomfortable task in most cases. What could be better than sitting in an air-conditioned computer room and having instant access to key points on a machine for performing fact-finding, root-cause analysis of difficult vibration problems?

First, let's list some desirable online system concepts:

- Frequent, on-demand sampling
- Accessibility
- Repeatability
- Speed and phase information
- Conditional data collection
- Frequent alarm checking and notification
- Action output via contact closures

These systems also lend themselves to the following applications:

- Intermittent start and stop operations - e.g. overhead cranes
- A mix and match of process variables along with vibration signals
- IF/THEN logic for conditional data collection based on speed, current, and other process variables
- Quick data scans for fast action on alarm notification on an overall value
- Polling of data on the key machine points
- Data thinning for efficient data storage and analysis
- Alarm condition notification by pc graphics, text messaging, and/or e-mail
- OPC connectivity to SCADA systems for data merging and presentation
- Browser viewing of data via Internet connections

Even with these benefits, there are traditional barriers to such an undertaking:

- Cost of hardware components
- Installation costs
- IT systems knowledge and involvement
- Systems training
- Maintenance and updating
- Lack of first-hand equipment condition observations
- Lack of systems interconnection integrity checks
 
There have been some recent technological changes to help the cause:

- Declining hardware costs
- Declining sensors costs
- Better, more capable and more reliable systems integration
- Wireless connectivity
- Complementary and compatible walk-around hardware
- Scalable system architecture

Users have stated that online systems technology fits best in the following applications:

- Dangerous locations
- Hazardous locations
- Remote and inaccessible locations
- Critical equipment
- Expensive equipment
- High maintenance equipment
- Equipment with known physical make-up and known failure modes and alarm thresholds

Experience has established the following key steps for a successful online system implementation:

- Start small in terms of number of points and data collection logic
- Prove out the initial concepts for system performance
- Be successful in fault finding and correction early on
- Document the results
- Recommend and implement system expansion
- Implement additions to the installed base

Tip provided by, Dennis Shreve CMRP, Support Engineer, Commtest