GE Industrial Solutions POWER LEADER ModBus Monitor - Manual (Page 49)

POWER LEADER Modbus Monitor
Chapter 7 – Advanced Configuration
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Add Register
Click Add Register to enter a new register:
Figure 48. Monitor Configuration Tool: Add Register dialog box.
Enter the register mnemonic, the register type, the
numeric register address. Select the register format and
the scaling factor from the pull-down lists. The table
below describes each field in more detail. Refer to the
device’s documentation for more information.
Register
Mnemonic Text string, no spaces or special characters.
Register
Type R0 - coil R3 - input
R1 - contact R4 - holding
See device documentation for details.
Register
Address Decimal integer only.
Range 0 - 9999 for standard addressing.
Range 0 - 65535 for extended addressing.
See device documentation for correct range.
Register
Format See Appendix C for more information. The Modbus Monitor
does not support any Register Formats not shown in this
pulldown list.
Scaling
Factor Default = 1. Select other scaling factors from pulldown list.
Register is multiplied by this value prior to being displayed
on the Monitor’s screen.
Click OK when the register information is complete. The
register will now appear in the register map list.
Modify Register
To modify an existing register, select it from the register
map list and click Modify to change any of its attributes.
The dialog box to change an existing register is the same
as to add a new register, but instead of coming up blank,
the current values for each register attribute are
displayed. Make any appropriate changes and click OK.
Delete Register
To delete a register, select it from the register map list
and click Delete Register. The register will be removed
from the list and also from any custom screens on which
it has been displayed.
Utilized Register Block List (URBL)
Because of the nature of Modbus RTU communications,
where obtaining a register value requires the master to
query the slave and the slave to send a reply, when you
wish to obtain several register values it is more efficient
to request them all together in a single block. The master
will only have to send one request and the slave will
only have to send one reply, even though the reply
contains additional data.
The Modbus Monitor supports up to 10 blocks of
registers for each register type. A block may contain
from 1 to 125 registers. The register addresses must be
contiguous; that is to say, no holes or skipped addresses
are permitted. If you wanted to obtain data from registers
at addresses 1000, 1015, 1040 and 1042, you would
create a single block of registers starting at 1000 and
ending at 1042 by defining each register in between,
without skipping any, even those of no interest. The
only exception to this rule is that some registers, such as
floating point registers, may occupy multiple addresses;
you are not required to enter each of these addresses,
only the first one. This should be evident from the
device’s register map, where the address will probably
be listed as (for example), 1000-1003.
The idea of register blocks becomes important when you
attempt to customize screens of data, because the
Modbus Monitor will look at the register fields for
display on a screen and will only request up to 10
register blocks. If all the registers you are attempting to
display can be retrieved by requesting 10 or fewer
register blocks, the screen will be displayed correctly. If
more than 10 register blocks must be requested to