Safety Switches for Material Handling Plants

The Trip Indicator unit consists of main display unit (Trip Indicator) located in control room and communication cards to be mounted in each safety switch located in the field. When any safety switch gets operated, conveyor will trip INSTANTLY and signal sent to the Trip Indicator from where TRIP relay o/p is generated; accordingly the operated switch number is displayed and communicated to PC/ PLC as per requirement.

The Trip Indicator system is offered in different models as below

Trip Indicator Model: TRS

Features like Auto Reset, Roll Call, Bypass, Individual Addressing, Binary O/P etc. are the unique features which are available now only with PROTOCONTROL make TRS model.

Trip Indicator Model: TRA

TRA model is economical than TRS model having only basic features, These models are self addressable types and requires termination module for their proper functioning. These are working on analog principal.

From the above models TRS model is most versatile model having all required/additional features. Multiconveyor indication system is also available with different options. The panels with required numbers of trip indicator units can be supplied.

Comparison between TRS AND TRA Models.

1. TRS models are working on advanced digital technology principal where as all TRA models are working on old analog principal.
2. Addressing of individual safety switch is possible in TRS model only. But it is not possible in TRA model as these are self addressable type. This means in TRS model every switch can be assigned permanent number (addressing facility). This number will not change even few switches are bypassed or removed for maintenance or any other purpose. ABSENT status of any safety switch will be indicated on display. However in TRA models the number will change causing unwanted miscommunication problems.
3. TRS models can work without termination module but in TRA model termination module is must for proper functioning.
4. TRS models are suitable to work for small as well long conveyors up to 20 Km. However TRA models are suitable to work for conveyor with limited distance.
5. TRS models can be used without any trouble even when safety switches used are in open environment area (work very effectively even though dust/ water contamination present in safety switch)

Protocontrol offer Cement Bag Counting system for online measurement of cement bags on conveyors. It consists of:

• Sensor
• Bag Display System (Counter)
• Setting Terminal

Selection of sensor and sensor location plays vital role in performance of the system. Various types of sensors are developed considering diverse applications.
The sensor can be

1. Limit Switch
2. Inductive Proximity Switch
3. Photoelectric Sensor.

Large size bright display for target and for actual production. Display height of 2 inch / 4 inch making it visible from distance. Setting terminal can be hanging type or with wireless interface facility.