Advanced Micro Controls Inc. 1700 Series User Manual page 43

Chapter 4 AMCI Module Addressing
Definition of Terms (cont'd)
2-Slot Addressing
Two slot addressing assigns one I/O group to each slot pair in the chassis. Block transfers
use the I/O group for control bits. You cannot use 32 bit single transfers if the chassis is
configured with 2-slot addressing.
1-Slot Addressing
With 1-slot addressing, one I/O group (16 I/O bits) is assigned to each slot in the chassis.
Therefore, a 1700 module has two I/O groups in its slot pair, one in each slot. Block transfers
use the odd numbered I/O group for control bits. When using 16 bit transfers, the position
value is in the odd numbered I/O group. When using 32 bit single transfers, the position data is
at the even I/O group, the tachometer value at the odd I/O group.
½-Slot Addressing
With ½-slot addressing, two I/O groups (32 I/O bits) are assigned to each slot in the chassis.
Therefore the 1700 has four I/O groups in its slot pair, two in each slot. The 1700 module does
not use the first or second I/O groups. Block transfers use the third I/O group for control bits.
When using 16 or 32 bit single transfers, the third I/O group contains the position value. When
using 32 bit single transfers, the tachometer value is in the fourth I/O group.
Addressing the 1700 as a Block Transfer Module
When configured as a block transfer module, the processor reads data from the 1700 with
block transfer read (BTR) instructions. If enabled with the PLC Program parameter, the
processor can program setup parameters and issue auxiliary commands with block transfer
write (BTW) instructions.
The block transfer address is made up of four digits. They are the I/O Rack Number (two
digits), the I/O Group Number (one digit), and the Module Slot Number (one digit).
Addressing Shortcuts
hý Always base the address on the slot the PC Board plugs into.
hý 2-slot address: Slot number always equals one.
1-slot address: Group number always odd, slot number always equals zero.
hý
½-slot address: Group number always even, slot number always equals zero.
hý
4-2
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The A-B backplane interface IC was designed primarily as a block transfer
controller. Because of this, 16 bit single transfers with 2-slot addressing
may not work with some processors. It is the users responsibility to test 16
bit single transfers in the system to determine if transfer operates correctly.
The A-B backplane interface IC was designed primarily as a block transfer
controller. Because of this, 32 bit single transfers with 1-slot addressing
may not work with some processors. It is the users responsibility to test 32
bit single transfers in the system to determine if transfer operates correctly.
M O D U LE A D D R E S S = R G S
I/O R ack N um b er
I/O G roup N um ber
M odule Slo t N um ber
Figure 4.1 BT Module Address
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