Hi,you will have to research both the manufacturer of the machine,and the input/outputs,from the machine to the panel. It's age would suggest,at least some of it's components have been changed,maybe not like for like.
The testing and monitoring of it's safe operation,depends on knowing what the design spec was,and only the manufacturer can supply this.
Another reason for needing this information,is it is not uncommon,for industrial machinery to be in use for a great many years,with issues,faults,and original operating methods,bypassed.