# BASEstartm Classic DAS
for Siemens H1tm Protocol
Installation and User's Guide

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## 2.3.3 DAS SPT Block Usage

The ILAN$MAX_SPT_REQUESTS parameter specifies the total number of blocks that can be allocated in the SPT (support) global section. DASes use blocks in the global section for storing data structures and for doing device I/O. The SPT global section is sized by calculating the number of SMALL, MEDIUM, LARGE and EXTRA LARGE blocks that the section should contain. Some blocks remain for the life of a device and some are allocated and deallocated for each I/O operation. Table 2-6 shows the static blocks of each size that are used by the DAS.

Table 2-6 SPT Static Block Sizes
Block Size | Quantity1 | Block Type
--- | --- | ---
MEDIUM | 2 | Device
SMALL | 1 | Device 2
| 1 | Unsolicited point 2

1Quantity is quantity per device, per line, per server, etc.
2Only created if the device is marked "unsolicited".

Table 2-7 shows the dynamic blocks of each size that are used by the DAS. These blocks are created and deleted as the device does I/O.

Table 2-7 SPT Dynamic Block Sizes
Block Size | Quantity1 | I/O Type
--- | --- | ---
LARGE | 1 | Upload/download
| 1 | Read status
MEDIUM | 1 | Read/write 2
| 1 | Start/Stop 2
| 1 | Send/Receive message
SMALL | 1 | Any

1Quantity is quantity per I/O.
2The block size depends on the size of the IO_SIZE on the path definition. If the IO_SIZE is larger than about 400, the block size will be a LARGE block.

The size of the SPT global section can be tuned by changing the percentage of each kind of block that is created. Refer to the BASEstar Classic Configuration and Tuning Guide for instructions on changing the percentage of each size of block that is created in the global section.

## 2.3.4 Setting DAS-Specific Parameters

None of the parameters created for the DAS for Siemens H1 Protocol are dynamic. A device must be disabled and reenabled before the parameter modifications become effective.

The installation procedure for the DAS for Siemens H1 Protocol creates BASEstar Classic parameters to allow you to tune the DAS environment for accessing data in TI programmable controllers. These parameters are listed in Table 2-8.

Table 2-8 TI Parameters
Parameter | Description
--- | ---
ILAN$H1_TI_CR_BASE | This value specifies the starting block number for the control registers in the programmable controller. The value is specified as a "DB:XX" value. There is no default value for this parameter.
ILAN$H1_TI_V_BASE | This value specifies the starting block number for the variable memory in the programmable controller. The value is specified as a "DB:XX" value. There is no default value for this parameter.
ILAN$H1_TI_CR_SIZE | This value specifies the size of the DB block for control registers. The value is used to calculate which DB block to request when reading a CRXXXXX address. There is no default value for this parameter.
ILAN$H1_TI_V_SIZE | This value specifies the size of the DB block for variable memory. The value is used to calculate which DB block to request when reading a VXXXXX address. There is no default value for this parameter.

See Addressing Syntax for TI Devices for information on addressing for TI programmable controllers and how TI addresses are translated into Siemens H1 addresses.

## 2.3.5 Setting Up Plant Floor Equipment

To set up your plant floor equipment, see the Siemens documentation for your specific device.

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