Chain Length¶

For some blind types, we need to be able to calculate the length of chain needed (this is the chain that is used to open and close the blind).
The chain length has a default figure (eg 75% of blind drop) but we can also be able to adjust this figure in the detail line entry.
There is a field in the blind type to determine whether the chain length is asked for or not.

For Chain/control length, at the moment we can deduct an amount (by looking at 'Chain Length Deduct' or 'Chain Length %' in Blind Type Amend).
We still want to do this but then round down to nearest 100mm.
Therefore we have created a parameter in the blind type record to say ‘Round Chain Length Down to Nearest’.
This is an integer, not a flag.
So if the figure is set to 100 and the drop is 1925, and ‘Chain Length Deduct’ = 150, the chain length is calculated as 1700.

We now hold a minimum figure for drop of the blind, below which the chain/control length deduction is zero.
This field is called ‘Min. Drop for Chain Length Ded.’ and appears in the blind type record if ‘Chain Length’ is true.
The chain length deduction is now calculated as 0 if the drop of the blind is below ‘Min Drop for Chain Length Ded’ ie the chain length will be the same as the blind drop.

Depending on the drop of the blind, we now hold different criteria for the default length of the control/chain.
We can also apply a formula according to drop points.
Previously we only held data about the control length here.

There is a new parameter called ‘Calc Chain Length On Install Height’, which defaults to false.
If it is set to true, and the install height > 0, then the chain length is calculated on the install height rather than the drop of the blind.

This was fine but the rule applied for all drops of blind.
We can now hold this information according to the drop eg up to a 'Manufacture Drop Size' (Drop Blind Size) of 500mm, the ‘Chain Length Deduct’ may be 100mm instead of 200 etc.
This data is held in a tab called ‘Chain/Control Length and is picked up from there in the order entry.

The functionality works this way:

1. In the ‘Blind Type’ amend window, the user can set ‘Chain Length’ flag for this Blind Type.
2. When you add/edit the order detail, Chain Length field is displayed, if this flag is checked for this Blind Type.
3. By default it shows 75% of the blind Drop.
4. The user can correct the value of Chain Length.
5. When you change the drop of the blind, Chain Length will be also recalculated.

There is now a customer field in 'Blind Types > Chain Length' tab.
This means it is possible to set specific chain lengths for specific customers.
If a record is set up here, it will override the chain length settings in the blind type form.

Please note, if you select a motor (for example) you will not need a chain length, so we need some way of zeroising the chain length automatically.
There is now a new flag on the stock record called ‘Zeroise Chain Length’.
If an option is chosen with this flag set to true, then the chain length in the order entry is zeroised.

Stock Items > Chain Length

There is a new field in the stock record called 'Chain Length'.
If an option is selected and the Chain Length in the stock record > 0, it is saved in the 'Chain Length' in the order detail line and that amount is used in the child safety calculation.
If the chain length is too long, it should not recalculate the chain length, and a message will appear saying 'The chain length selected is too long. Please select an alternative chain'.
It is not possible to save the order detail line until this is satisfied.
This also applies to online ordering.

Blind Types > Chain(Control) Length > Formula
There is a new field for ‘Install Height’ in the Chain(Control) Length > Formula, which means chain lengths can be calculated on the install height.