The Satisloh Micro-Blocker is a manual blocker (it does not interface to Rx-Universe), with a limited set of blocking rings available. Two sets of blocking rings are commonly available (Starter Kit and Advanced Kit):
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53x7 (no prism)
53x10 (no prism)
58x7 (no prism)
58x13x2' (58x7 + 2' 58x6 prism ring)
58x13x4' (58x7 + 4' 58x6 prism ring)
63x7 (no prism)
63x13x2' (63x7 + 2' 63x6 prism ring)
63x13x4' (63x7 + 4' 63x6 prism ring)
68x7 (no prism)
68x13x2' (68x7 + 2' 68x6 prism ring)
68x13x4' (68x7 + 4' 68x6 prism ring)
So, the Micro-Blocker can block either no prism, 2 angular degrees, or 4 angular degrees of prism. The Micro-VFT can generate up to 2 angular degrees of prism, so as much prism as possible must be blocked in order to maximize the total prism on the job.
Setting Up Micro-Blocker Blocks in Rx-Universe
First, set up a Block Group for the Micro-Blocker, under "Setup", "Surface Block Groups":
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The blocks would be set up as follows:
Note that the dynamic selection is set up so that the blocking rings with prism are considered first.
When setting up the blocking rings with the 2' and 4' prism, note above that the "nominal height" for the 4' block is set as 14, not 13. This is necessary in order to make the block unique - we can't have two 58x13 blocks in Rx-Universe. So, the 3 58mm blocks should be set up as follows:
The amount of prism is 0 The block height is 13, prism is 2.00 Block height is 13, prism is 4.00
Toric Jobs
When calculating a toric job using the Micro-Blocker interface, Rx-Universe will calculate the prism required for the job, and then select the block. If there is a block available with prism that is <= the prism required, Rx-Universe will select that block and set the prism to be generated to the difference. In order to ensure that a block with the most prism possible is selected, the dynamic block selection should be set so that the 4' prism ring(s) are checked first, followed by the 2' prism rings, within each block size.
For example, consider the following job:
The prism required for this job is:
Keep in mind that the Micro-Blocker blocking rings have prism expressed in angular degrees.
Rx-Universe will thus select the 58x13 block with 2' of prism:
The amount of prism on the block is 1.74 (this is 2 angular degrees converted to prism diopters in 1.498 index).
Normally, the amount of "Blocked Prism" is set when the blocker requests the information from Rx-Universe, but since the Micro-Blocker doesn't actually interface, we set the "Blocked Prism" at the time of calculation.
Then, when the job is requested by the generator, we send the remaining prism (2.47-2.00=0.47 angular degrees, or (1.92-1.74=0.18 prism diopters):
The work ticket will display the blocking ring to be used, to the operator:
Note that since the blocker doesn't interface with the LMS, there is no way to confirm the right blocking ring is used. The responsibility thus falls to the lab to ensure proper blocking is done.
Digital Jobs
When using a Micro-Blocker and interfacing with a digital calculator, the digital calculator must support the Micro-Blocker interface. This is necessary because the digital calculator determines the amount of prism to be blocked (returned in KPRVM), the amount of prism that will be incorporated into the design (returned in LDPRVM) and the amount of prism to be generated (returned in GPRVM). There is no provision for an LMS to determine the amount of prism to be blocked and then inform the digital calculator, so the calculator itself must be capable of supporting the Micro-Blocker interface.
For example, with Crossbows digital calculator, the calculator must be set up to both select the blocking rings, and to use the Micro-Blocker interface. The blocks would be set up (under Database, Blocks" similar to:
Under "Tools", "Options", AutoBlockSelect must be set to 1, and theUseMicroBlocker option similarly set to 1.
Consider the following sample Crossbows job:
The LMS file returned from Crossbows will contain the following (file reformatted to display easier):
Here, Crossbows returns prism diopters in 1.530 index, which corresponds to the 2 angular degree prism ring, and the block size reflects the 58x13 block. In this case, there was no prism indicated for the generator.
As in the case of the toric example, the prism is designated as blocked prism:
And the work ticket will display the blocking ring to be used: