Encoder count missing in 1734-ib8

Dear All,
I have point IOs 1734-ib8 which is connected by an encoder resolution is 600 only but after using it losses count can any one idea how to make any program or overcome from this problem i am taking A signal out off A,B and Z.

These modules are not intended to be used as encoder inputs.

Take a basic look at the update times of your network and compare it to the frequency of your encoder signals.

You said it's a 600 pulse per revolution encoder. How fast is the encoder turning ?

Thank you Mr Ken Roach

here is my network update time.
its speed is 300 rpm.but also when i check this via a counter it is missing too much. should i buy high speed counter

encoder is open collector output with 1 microsecond reprocess time

Input filter time(1)
OFF to ON
ON to OFF
(1)
Input off-to-on filter time is the time from a valid input sig
nal to recognition by the module. Input on-to-off time is the
time from a valid input signal to recognition by the module.
0.5 ms hardware plus 0...63 ms (user-selectable)
0.5 ms hardware plus 0...63 ms (user-selectable

Click to expand...

You need an encoder module for an encoder, unless you have an extremely slow process.

Manuals are your friend, they actually have specifications related to the module.

600 pulses / revolution at 300 revolutions / minute times 60 seconds/minute = 3000 pulses per second.

Generally an encoder pulse is 50% on/ 50% off. For there to be 3000 pulses per second, each pulse would have to be on for 1/6000 seconds (.167 milliseconds).

Since the 1734-IB8 has a minimum 0.500 ms hardware delay built into its circuitry, it is inappropriate for this application just because of the hardware.

The I/O update for the logic controller is the principal limitation to using a general-purpose I/O module for fast signals like an encoder. In general you need an I/O update twice as fast as the expected signal.

A default 10 millisecond I/O update will allow you to sense pulses 20 milliseconds long. You have to sense both ON and OFF states, so the fastest signal you could reliably detect is 1 / 0.040 ms = 25 Hz.

All this is a long-winded way of saying "yes, you should use an encoder module".

The POINT I/O platform has two different kinds of encoder module; the IJ/IK and the VHSC.

The 1734-IJ and 1734-IK are the "encoder" input modules, and are good for measuring speed or frequency. The -IJ is for 5V inputs, the -IK is for 24V inputs.

The 1734-VHSC5 and VHSC24 are the "high speed counter" modules which are good for counting pulses and turning on local outputs based on those pulse counts.

Also, those network properties are for motion control networking and are not what I was referring to.

Instead, you need to look at the ordinary "Requested Packet Interval" for the 1734-AENT adapter module to which the 1734-IBx input modules are connected.

Or, if these modules are connected directly to a 1769-L16 or -L18 controller, you need to look at the connection RPI to the module on the backplane.

i will heartily thanks to Mr Ken Roach and RD rust.
i am looking 1734-vhsc24 module for this. i will buy local distributor. i am using 1769-L24er-qb1b with 1734-aent module
in star type network.Rather i have programed controllogix with expert level but never come to encoder and its use in rslogix5000. now i am using rslogix5000 v20. can i know how to configure encoder and take pulse values from it via vsc24 module.
thank you dear friends.