Is it recommended to have a separate ERP system to maintain payroll data?

It is Highly recommended to Have to a Separate ERP system to maintain payroll data but main thing they has to be a link the cater the Backup  

No, it is better to maintain One ERP for Finance, HR, Procurement, etc done maintain separate system for different modules

Thank you, I regret unable to answer due lack of information as well as experience in this side.

Best wishes.

Usually payroll is not considered as part of the ERP but I would recommend to be all from one vendor (SAP , Oracle, Microsoft , etc..) . 

I would view it as follows:

1) ERP : contains all the functionalities such as manufacturing , inventory , order management , etc..

2) HCM : Human capital management activities , managing employees , abscence , etc..

3) Payroll : Defining payment rules and other rules related to payroll and running the payroll

HCM is of course integrated with payroll and ERP (e.g linking the wages and attendance data with manufacturing for certain calculations) .

If you use different solution , integration won't be as seamless as you would need an interface or different method for your integration .

If you are a big or medium sized organisation you can use SAP / Oracle as an ERP for all your HCM requirements. There is no need to have separate ERP for payroll purposes. 

yes why not not if you want to  improve qualilty of Service,you also have information at your fingertips ,having ability to deliver real-time information on-the-spot and  entering relevant data accurately as they gather it in the field without re-keying the data into back end systems.and also if your ERP is not abstract nature.