Dataforth MAQ20-RTD31, Hardware User Manual

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MA1044 MAQ20-RTD31/-RTD41 Hardware User Manual
Page 14 of 38
12.0 MAQ20 I/O Module Registration and Reading Input Signals
The MAQ20 Data Acquisition System uses an automated registration process which periodically
scans the system and will detect when MAQ20 I/O modules are added and removed. Modules are
assigned a sequential Registration Number based on the order in which they are detected. This order
can be forced to occur in a given sequence by adding modules one at a time or it can be allowed to
happen randomly. Refer to the
Building a System , Maintaining a System, and Expanding a System
sections for further details.
The system does not identify I/O modules by physical position on a backbone, only by registration
sequence. MAQ20-940 ReDAQ Shape Software for MAQ20 provided by Dataforth shows a graphical
representation of a system based on registration sequence and not by physical position. Tools within
the software package allow the user to reassign Registration Numbers thereby making graphical
representations match physical location for a single, local backbone.
Module Detect: A write to the Module Detect register at I/O module register address 98 plus the
module offset based on Registration Number will blink the STAT LED on the top angled surface of
the module at a 5Hz rate for 5 seconds so the module location in a system can be visually identified.
Each module is assigned an address space of 2000 addresses based on the Registration Number
and starting at address 2000. I/O module with Registration Number 1 is assigned address space
2000
– 3999, I/O module with Registration Number 2 is assigned address space 4000 – 5999 and so
on. The starting address for the module is very important because this is the offset address that must
be added to the addresses listed in the I/O module register address map to know where data for that
module is located within the system level address map. The MAQ20-COMx Communication Module
is always assigned a Registration Number of 0 and cannot be re-sequenced.
Table 4: MAQ20 System Register Address Range & Module Register Address Range
Registration Number System Register
Address Range
Module Register
Address Range
Register
Address Offset
0 0 to 1999 0 to 1999 0
1 2000 to 3999 0 to 1999 2000
2 4000 to 5999 0 to 1999 4000
3 6000 to 7999 0 to 1999 6000
… … … …
24 48000 to 49999 0 to 1999 24000
The automated registration process can be disabled and I/O modules can be registered using a
manual process if required by an application. Refer to the MAQ20 I/O Module Registration section of
the
MA1040 MAQ20 Communications Module Hardware User Manual for details.
The standard mode of operation is called Continuous Scan Mode. All channels are enabled and input
readings are taken by sending a read request command to the module. In Burst Scan Mode, channels
can be selectively enabled.
The
MAQ20-RTD31 Address Map and MAQ20-RTD41 Address Map are found at the end of this
manual. An excerpt from the MAQ20-RTD31 Address Map is shown below. Channel Data is stored
starting at module register address 1000, which is system register address 2000 * R + 1000, where
R is the module Registration Number.
Table 5: MAQ20-RTD31 Address Map Excerpt
– Module Data
Address Range 1000 - 1699 : Module Data
Start
Address
Read/
Write
Number of
Registers
Contents Description Data Range
Data
type
1000 R/W 6 Channel Data
Data for each of 6
Channels See Table 7,
Table 8
INT16