# 8.2 Installment

**Introduction**

In order to effectively protect the interests of users, HMI provides the function of installment payment; there are two types of installment payment mode, static and dynamic.

**Description**

![](https://3950998874-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2Fpi-series-user-manual%2F-Lv4jr574fhYvHZaXX04%2F-Lv4jvyY5khBOzQ4JtqJ%2F0.png?generation=1575275708984042\&alt=media)

**1) Static mode**

The expiry time and key of each period could not be empty, and they need to be configured in advance. And the expiry time of the latter period need to be later than the expiry of the previous period.

**Use admin key:** It can be used for unlock all expirations, in addition to each period key. If users select \[use admin key] function, once users enter the admin key when HMI expires, the installment payment function will be disabled.

Admin: Password (Key) for \[use admin key];

**Max periods:** The period of static installment payment range is 0-12. When the maximum number of period is 0, it means that the instilment payment function is disabled;

**Begin Period:** Set the installment payment to start from the first period, the range is 1-13;

**List:** Configure a list based on \[Maximum Periods] and \[Begin Period], where user can configure the password and expiration time for each period.

**2) Dynamic mode**

Just configure the password and expiry date in advance. The user generates a \[dynamic password] through enter password and expiry date in \[Generate Password Tool]. Users can enter new dynamic password when HMI expires, and the screen can be re-used to the expiry of the next new setting. See \[[Password Tool](https://wecon.gitbook.io/pistudio-manual/13.tools/13.7-password-tool)] for details.

**Password:** The initial password for the installment credit;

**Expire Date:** Date setting for first payment;

**Current Time:** Display the current PC time;

**Valid Days:** counting the days before first payment;

**3) Common settings**

**Set Bit:** Set bit when HMI displays the installment screen.

**Clear Bit:** Clear bit when user enters the right installment password.

**Upcoming Alert:** HMI show the installment alert before expire date (before 1,3 or 5 days)

✎**Note:**

1\) In static mode, when \[Begin Period]>\[Maximum Period], it means that the installment payment function is disabled, that is, the installment payment function is invalid.

2\) The password could not exceed 8 bytes in length;

3\) The legal characters of the password are "A-Z, a-z, 0-9";

4\) Password is case sensitive.
