HS-421 4–20 mA vibration sensor (velocity) with additional AC output, top exit, M12 connector
- AC IEPE + 4–20 mA
- Top exit
- IP67
- M12
PDF datasheet
Pharmaceutical: machine vibration monitoring
In pharmaceutical production, a machine failure can mean a lost batch, a deviation from the validated process and additional documentation. Vibration monitoring of air handling units, utility equipment and process machines helps maintain production continuity and plan maintenance work within agreed service windows.
What fails most often
Every unplanned interruption to a process operated to validated parameters requires investigation, an assessment of the impact on quality and often a decision on what happens to the batch. Planned work can be prepared in advance together with the quality and production departments; a breakdown cannot. Knowing the condition of machines therefore helps not only to avoid downtime but also to organise maintenance work.
Utilities and HVAC — less visible, equally critical
Cleanrooms depend on air handling units, which maintain the airflow and the pressure cascade. A damaged fan bearing can stop production in an entire zone, as can the failure of a pump in the purified water loop, an air compressor or a chiller. This equipment runs continuously, often in plant rooms and on roofs, where staff rarely go.
On qualified equipment, sensors are installed under the change control procedure, and in clean areas it is important to use materials that withstand frequent cleaning and disinfection. Where solvents are used, there may be hazardous areas.
Typical machines
- Air handling units (AHU)
- fan unbalance, misalignment, bearing damage
- Purified water, dosing and circulation pumps
- cavitation, bearing damage, mechanical looseness
- Process drive motors
- bearing damage, unbalance, misalignment
- Mixers and granulators
- bearing and gearbox damage, mechanical looseness
- Gearboxes and conveyors on tabletting and packaging lines
- gear tooth wear, misalignment
- Air compressors and chillers
- bearing damage, unbalance, mounting looseness
From the machine to the monitoring system
01Machines in this industry
Air handling units (AHU), purified water, dosing and circulation pumps, process drive motors and others — measuring point on the bearing housing.
02Sensor
An IEPE accelerometer or a 4–20 mA sensor converts vibration (and often temperature) into an electrical signal.
Industrial IEPE accelerometers
03Signal
A cable with the right connector and a junction box carry the signal from many measuring points to the system.
Cables and connectors
04Monitoring
PLC, DCS, an online system or a data collector: trends, alarm thresholds and diagnostics before a failure happens.
Vibration systems and switches
How to choose the measurement
Air handling units: 4–20 mA to the BMS or PLC
A simple and economical way to monitor air handling units is to use HS-420 transmitters mounted near the fan and motor bearings. The 4–20 mA signal, proportional to vibration velocity, goes to the BMS or PLC, where the trend of the overall vibration level is available remotely and an alarm is raised when a threshold is exceeded. This approach mainly covers unbalance and misalignment — see 4–20 mA vibration sensors.
Dual output: trend and analysis from one point
HS-421 combines a 4–20 mA output (vibration velocity) with an AC output (acceleration). The control system receives a continuous trend, and a maintenance engineer can connect a data collector at the same point and carry out detailed analysis: detect bearing damage and mechanical looseness, and confirm the cause of unbalance or misalignment. See 4–20 mA transmitters with AC output.
Long-term trends from reading points
Permanently mounted HS-100 accelerometers connected to HS-SE switch boxes in an accessible, safe place — for example, a technical corridor — allow data to be collected regularly from the same points without entering the cleanrooms. Where access is limited, the side-exit HS-100S version works well.
Areas where solvents are used
If the explosion protection document defines Ex zones, for example in areas where solvents are handled, intrinsically safe versions are needed — see accelerometers for hazardous areas. You will find the certificates and Ex marking of each version in its documentation.
Recommended versions
Dual output: 4–20 mA for the PLC and an AC signal for analysis.
HS-100S Industrial AC accelerometer, side exit, M12 connector
- AC IEPE
- 10 … 500 mV/g
- Side exit
- IP67
PDF datasheet
Side exit where access is limited.
HS-SE-TX-PC HS-SE series Polycarbonate switch box for triaxial sensors
- IP66
- 3 axes
PDF datasheet
Switch box — a readout point for the data collector.
HS-100 Industrial AC accelerometer, top exit, M12 connector
- AC IEPE
- 10 … 500 mV/g
- Top exit
- IP67
PDF datasheet
Accelerometer for long-term trend analysis.
HS-420 4–20 mA vibration sensor (velocity), top exit, M12 connector
- 4–20 mA
- Top exit
- IP68
- M12
PDF datasheet
4–20 mA for air handling units (AHU) and BMS.
Product groups for pharmaceutical
- 4–20 mA vibration sensors (LPS) HS-420 for air handling units and integration with the BMS or PLC.
- 4–20 mA transmitters with additional AC output HS-421 — a 4–20 mA trend in the system and an AC signal for detailed analysis.
- Industrial IEPE accelerometers HS-100 and HS-100S for long-term trend analysis, also where access is limited.
- Multi-channel switch boxes HS-SE switch boxes in the technical area — measurements without entering the cleanrooms.
- Accelerometers for hazardous areas (ATEX / IECEx) Intrinsically safe versions for areas classified as Ex zones because of solvents.
Industry questions
How do I choose the measuring range of a 4–20 mA vibration transmitter for an air handling unit fan?
The range should cover the normal vibration level with a margin for the warning and alarm thresholds, but it must not be too wide, as this reduces the resolution of the reading. The range is chosen when ordering, from the options given in the datasheet. Alarm thresholds can be based on vibration evaluation criteria for fans, e.g. from ISO 14694, and on measurements taken after commissioning.
What does the HS-421 dual-output sensor offer?
The HS-421 sends a continuous 4–20 mA signal proportional to vibration velocity to the PLC or BMS, and at the same time provides an AC acceleration signal for analysis with a data collector. One sensor at one point therefore serves both for continuous monitoring and for diagnosing bearing faults and looseness. This simplifies the installation and the documentation of changes to the equipment.
Does mounting a sensor require the air handling unit to be shut down?
Usually, yes, because the sensor is mounted near the bearings in the fan section, which can only be accessed safely once the unit is switched off. It is worth combining the work with a planned inspection of the air handling unit. If a tapped hole cannot be made, use an adhesive mounting pad, which does not require machining of the housing.
Further reading
- How to choose a vibration sensor for your machineChoosing a vibration sensor starts with the question of where the signal will go. Step by step, we cover the output type, measured quantity, sensitivity, frequency range, operating conditions, connection type, mounting and number of axes — with a checklist at the end.
- Vibration sensors in Ex zones: a selection and installation guideIn a hazardous area, a vibration sensor is part of the explosion protection system, not just a measuring instrument. We explain zone classification, the principle of intrinsic safety, the role of barriers and what to check in the certificate and documentation.
Monitoring HVAC and process machines
Send us a list of the air handling units and machines you want to monitor, together with information about your BMS or PLC. We will help you select sensors and compile their technical documentation.