Sna Discrete To Analog Register Bit Position Mapping; Determining The Mapping - Raco Catalyst Owner's Manual

to the lower registers plus some margin for additions and then assign the Analog
channels above that range.
To allocate space for 50 Discrete alarms: Each Analog register requires 16-bits. 50
divided by 16 = 3.125 so that would make the first 4 Analog registers unavailable. The
first Analog SNA free would be 1*2*40005 as well as all the registers above that.
To determine the exact bits used by an Analog channel: The first bit is found by
this equation {(Analog SNA -40001)* 16} +1. Analog SNA 1*2*40005 would be
{(40005-40001)* 16} +1 = 65. The Discrete bits used would be SNA 1*2*00065 and
the next 15, ending at 1*2*00080.

SNA Discrete to Analog Register Bit Position Mapping

Each Analog register consists of 16 individual bits, numbered from 0 15. There are
numerous ways that that the single bit Discrete register addresses can be mapped to
these bit positions and can vary with different PLCs. We will discuss the common
options here. If these do not match your scenario, please contact Technical Support
and we will gladly assist you.

Determining the mapping

Numerous standards and variables can make determining the end-to-end mapping
that your system uses. Rather than going through the process of determining the
exact mapping that your system uses, it can be faster to do a quick test to locate the
correct mapping to find a specific bit. This will also verify that the system is working
properly.
1. Verify the correct Analog Register address: Monitor the status of the bit in
question. Write FFFF-hex to the Analog register that you suspect contains that
bit. The bit in question should be set to 1 as FFFF-hex will set all the bits in that
register to 1 since FFFF-hex= 1111 1111 1111 1111). If not, then the
addressing is incorrect, or there are other issues that must be resolved before
continuing. A common problem is that the addressing is off by one, so try the
Analog registers that are immediately before and after it.
Saved: 2015-08-03
Filename:
Catalyst EtherNet Option Setup R5 V01.docx
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