RELIANCE CONTROL LIMITED
Elevator Controls / Embedded Design and Support
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HELP CENTER
Regular Questions and manuals to provide a basic information for those interested, only qualified Technicians should carry out adjustments.
IS A HAND TERMINAL REQUIRED FOR AN ENCODER LEARN ?
Yes, a Hand Terminal is required when installing a new Position System, this is because the learn sequence for the encoder is issued from the Hand Terminal.
After a learn and the Correct levels function has been completed the Hand Terminal is not required.
A New learn is required when replacing a PSE Board as the Shaft Parameters are stored in the Encoder board not the Controller. The manual can be found below.
WHY DO I NEED TWISTED PAIR CABLES ?
There are some complex Physics behind this but to give a very Basic understanding. Twisted pairs are important for Serial Communications that use a Differential signal such as CAN/RS485, also some Motor Encoders. This means that the same data is on each conductor, but they are compliments of each other, quite often signified as a H(High) & L(Low) on CAN bus and + & - on others.
Simplified, the receiver only detects the differences (compliments) between the pairs, known as Common Mode Rejection.
The Twist induces any Electrical Interference picked up on one conductor to the other, so if both have a Positive spike then this is ignored/rejected.
WHAT RESISTANCE SHOULD I READ ON A CAN NETWORK?
It is important that each CAN Network has the Correct Line Loading (Resistance)
A CAN Networks Topology requires that there should only be Two Ends.
e.g On a Landing Network there will be a Resistor at the Bottom of the Shaft Riser loom and another at the Controller end.
A Rule of thumb is to Place a 120 Ohm resistor on each end of the network.
Across the CAN High & Low Signals.
As the resistors are in Parallel a reading of 60 Ohm's or close should be measured with a Multi Meter. The Supply including any Battery backed supply must be off before a reading can be taken.
For more information Download the training notes below.
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HOW DO I KNOW IF I HAVE A 6 POLE OR 4 POLE MOTOR ?
Quite often we get asked, how do I know how do I know how many poles does my motor have ? as its not on the data plate. A VF Drive will turn a motor even if the incorrect poles are entered albeit it wont be a pretty profile.
We are referring to 3 phase Induction motors, these are the most common ones with a combined Gearbox, NOT Gearless Motors.
A simple answer is the more poles the slower the Machine is e.g.
A 6 pole Machine will be approximately 900 to 1000 RPM depending on Slip.
A 4 pole Machine will be approximately 1300 to 1500 RPM depending on Slip.
Why ? The calculation is very simple:-
The formula uses a fixed constant of 120 this is easy to remember. Just think of 2 Minutes worth of seconds as we are working in Revolutions per minute and Poles actually are in pairs.
Then you need the Frequency, in the UK we use 50Hz.
So the formula is :-
RPM = (120*50) / number of pole pairs.
So a 4 pole motor = (120*50) = 6000 then 6000/4 = 1500 RPM
This is known as the Syncronous speed. In reality the motor doesnt run at this speed due to Physical limitations so quite often the RPM on the data plate will be less e.g 1430RPM.
Now what is Slip ?, Slip is the difference between the Syncronous Speed and the Rated speed it can be expressed in RPM or % This will be covered in the VF Drive Basics document.
I CANNOT CORRECT LEVELS AFTER AN ENCODER LEAN
Firstly check there is no Roll back and the lift has a controlled stop (e.g. Not slipping on brake) also it is best to disable Pre-Opening feature during correction.
Some systems had a Direct to floor feature whereby an additional Magnet was used to define a travel dictated by the Drive unit. This can interfere at levelling. It is advisable to disable this feature in the Unidrive SP , Parameter 10.14 set this to 0 (OFF) Remember to save this by going to any nn.00 Parameter and setting to 1000.