For the banks I know, the location of the ATM determines the limit. For example, BOC in a metro station allows only 3000 RMB in a single draw but a bank location allows more, like 5000 or 10000. For domestic cards the limit is 20k per day and you can withdraw that in multiple consecutive transactions regardless of the single draw limit. Don't know if that applies for foreign cards but it may be similar. If you want more than the single transaction limit, just try a second time.