Hi All,

I have been working for many days now on trying to interface an IFM encoder (A, B, Z) to my S7-1200 PLC. (https://www.ifm.com/ie/en/product/RB3500)

My Connections: I have A on 00, B on 01 an Z on 6.( 00 and 01 being HSC)

I am able to get the  plc to increment in 2s in one direction only. In reverse it only switches between 1 and 0.

Lights are flashing in sequence.

Because the switching frequency is 1000 kHz, could this be the problem ?

Any ideas, hints and tips ?

Any assistance is appreciated

Hello im working with Espiral so ill give some more details.

We are using the seimens s7-1200 AC/DC/Rly connected to a incremental encoder from ifm (RA3100). The main issue is that when using the HSC we can only count up in units of two and are unable to count back down. We are using HSC_2 (enabled) using the following settings:

Type of Counting: Count

Operating Phase: A/B counter fourfold

Initial Counting Direction: Count Up

Clock generator A Input: %I0.2

Clock generator B Input: %I0.3

If you have any advice or links that could help us out it would be greatly appreciated.

The Manual for the encoder can be seen in the attachment.

The encoder connection in the second post is different from the first post.

What firmware version is your cpu? What version is your software?

- Make sure you enable and configure HSC

-In hardware configuration select lowest possible "filter" setting for the digital inputs you will be using.

- In Device View right click on the CPU and select download hardware configuration.

-Wire the encoder's A and B to the inputs specific to the HSC you enables. Don't wire Z for now

- Check to make sure your counting up and down.

Firstly, thank you for your assistance.. 

I will answer a couple of questions then let Allech take the reins from my end as he has a better idea on what is happening (and changed my IO assignment :) ).

To answer a couple of your questions (with reference to the my datasheet):

• CPU = 1212C AC/DC/RLY
• Software = STEP7 Basic

(all forming part of kit 6AV6651-7KA01-3AA4)

Information from IFM:

The encoder is configurable (with IFM IOlink) and ships with the default output being HTL. I think it would be prudent to double check this.