Modbus Operation - Hoffman Controls 890-DSQ Series Complete Installation & Operating Instructions

Modbus Operation

IMPORTANT:
After remotely updating any information the re-
mote operator MUST review ALL of the 890-DSQ
Sequencer's mode, menu, submenu and numerical
value options to 1) ensure that all of the operating
parameters, needed for the application, have been
correctly selected and 2) also ensure that any un-
needed or undesired options or numerical values
have not inadvertently been left selected.
To update any or all of the 890-DSQ Sequencer's mode, menu
and submenu parameters and numerical values remotely, using the
Modbus RTU connection, proceed with the following steps:
1) Set MODBUS RTU address, baud rate and parity for
each 890-DSQ slave sequencer installed.
2) Write to each slave using the TABLE 2A & TABLE 2B
information (pages 16 & 17) to select the 890-DSQ
Sequencer's internal register numbers and associated
data, as required, to set up the sequencer's operating
parameters and numerical values.
NOTE: Reliable operation is obtained only when using
the data values described in the Operating Modes
scetion (pages 4 thru 9) or shown in Figure 3 (pages 10
& 11).
3) Use Modbus RTU command 3 to read data from indi-
vidual or multiple internal sequencer registers.
4) Use Modbus RTU command 6 to write data to an indi-
vidual internal sequencer register.
5)Use Modbus RTU command 16 (hexadecimal 10) to
write data to individual or multiple imternal sequencer
registers.
6) Recheck all Modbus register data, not just the changed
data, and verify all the data is correct.
7) Observe the 890-DSQ Sequencer's operation, thru an
entire system's cycle, to ensure correct operation.
IMPORTANT
Remotely viewing or updating the 890-DSQ's
register data can only occur when the sequencer's
Home Screen is displayed on the LCD. If an
installer is simultaneously observing or updating
the 890-DSQ's menu, submenu or numerical
values manually, the installer must return to the
LCD's Home Screen before a remote update can
be preformed.
:
18
Sequencer Re-calibration
If re-calibration of the 890-DSQ Sequencer's settings or numer-
ical values are required, due to the particulars of the application,
proceed with the following steps:
1) Power up loads (motors, heating elements etc.) and 890-DSQ
Sequencer.
2) Determine if local, remote or a combination of both local and
remote operation is to be used.
a. When local operation is desired, enter the Lockout
Code, if needed, then use the sequencer's five (5)
push buttons and the LCD screen's information to
select the settings and numerical values made avail-
able by each mode, menu and submenu screen.
Follow the Operating Methods and Operating
Modes sections (pages 3 thru 9) to update the
settings and numerical values. Also follow the Built
In Test Section (page 13).
b. When remote operation is desired, follow the Modbus
Operation section (this page) and the Operating
Modes section (pages 4 thru 9), along with TABLES
2A and 2B (pages on 16 & 17), to update the settings
and numerical values.
c. When a combination of both local and remote opera-
tion is desired, follow the instructions in 2a) and 2b)
above. Local or remote operation can be used to
initially operate the system. The installer can then
observe and monitor the system's operation, and localy
update any parameters that allow the Sequencer to
provide the best operation for the application.
Final Sequencer Checkout
Reconnect any previously removed wires & verify the all the
wiring is correct and complete. Apply line voltage to the motors
(or SCRs and heating system), then apply 24 VAC power to the
890-DSQ Sequencer and observe the system's operation. If the
system works correctly, no operational updates are needed.
If the system does not work optimally, determine the specific
cause for the anomily and fix it. When the anomily's solution
involves an update to the 890-DSQ Sequencer's data registers,
Operating Modes
follow the
update the specific data register(s) needed to achieve the best
possible system operation. After the update(s) have been made,
observe the entire system's operation again, to verify the update(s)
worked.
instructions (pages 4 thru 9) to