If you are referring to data log in a SD card, here you have an example posted on our blog which explains how to generate a datalogger using the internal microSD card slot. In the attached example, an analog value from a temperature sensor is stored internally inside the SD card periodically (MDuino PLC used as example):

https://www.industrialshields.com/blog/arduino-industrial-1/post/analog-datalogger-in-sd-card-87. 

 Regarding the Zebra printer label, We do not have any specific example about  how to communicate with label printers like Zebra but, if you let me know which communication method uses or how it is connected to the PLC, maybe we have similar examples that can be useful.

Usually they work over RS232 protocol, herre you can check how to use RS232 in Arduino based PLCs from Industrial Shields using IS libraries: 

https://www.industrialshields.com/blog/arduino-industrial-1/post/how-to-use-rs-232-on-industrial-arduino-based-plc-16

If this concrete Label printer uses a different communication port / protocol, let us know which is in order to help you, 

Cheers,