Basler Electric BE1-700 Modbus Protocol - Manual (Page 26)

1-16 BE1-700 Modbus™ Protocol 9376700991 Rev D
example, a user cannot make changes from COM0 at the same time a remote user is making changes
via Modbus from COM2.
Changing the settings through the Modbus port requires that the operator write to the ACCESS
REQUEST register to obtain programming access. This must follow writing the ACCESS PASSWORD
register(s) with a password to obtain access to change settings associated with the password. Different
passwords give the ability or access to perform different operations. The relay will deny access if an
invalid password is entered or if another user has already been granted programming access through
another serial port or at the front panel. Only one user can have access at any one time.
If no password protection is used, it is still necessary to obtain access in order to protect against
accidental changes. If password protection is disabled, then writing the ACCESS REQUEST register will
be accepted in place of a password. The relay will transmit a valid response message if the access query
was received and executed. The relay will respond with an error message if the access query could not
be executed.
Changing settings through a Modbus communication port consists of the following sequence:
Step 1. Preset Multiple Registers query to ACCESS PASSWORD register(s) to specify password.
Step 2. Preset Multiple Registers query to ACCESS REQUEST register to access write privileges.
Step 3. Preset Multiple Registers queries to change the current settings.
Step 4. Preset Multiple Registers query to EXIT register to clear access and save.
Changes are not made to the working settings but to a scratch-pad copy of the settings. After the
change(s) are made, the new data will be copied to the working settings and saved to non-volatile
memory when the EXIT register is written with a 'Y.' It is important to make all changes to relay
parameters before writing the EXIT register. This prevents a partial or incomplete protection scheme from
being implemented.
Template Registers
The BE1-700 uses three templates. A template is a block of holding registers to which the user assigns
one of a number of similar groups of parameters. Templates are used for settings groups, fault
summaries, and report generation. Modbus Template Registers 40036 (Settings Group Selection), 40038
(Fault Number Selection), 40039 (Report Selection) and 40040 (Report Focus) do not require any Write
Password Access level before they can be written to.
The BE1-700 has two settings groups. The GRP template is assigned the parameters of a settings group.
Therefore, before reading or writing settings group values, a user must first specify which settings group
is to be associated with the template. This is accomplished by writing the desired settings group number
(0 or 1) into the SETTINGS GROUP SELECTION Template holding register.
The BE1-700 stores up to 12 faults. Each fault is accessed by its fault number which ranges from 1 to
255. The FLT template is assigned the parameters of a particular fault occurrence. Therefore, before
reading fault summary values, a user must first specify which fault number is to be associated with the
template. This is accomplished by writing the desired fault number (1-255) into the FAULT SELECTION
Template holding register.
The BE1-700 generates 10 ASCII reports. The RPT template is assigned the text of a report. Therefore,
before reading report text, a user must first specify which report is to be associated with the template.
This is accomplished by writing the desired report number into the REPORT SELECTION Template
holding register along with the associated report identifier, if any, into the REPORT FOCUS Template
holding register.
Fault Summary Registers
The user can enter any fault number (1 - 255) into the FAULT SELECTION Template holding register to
associate summary parameters for that fault number with the FLT Template. The Fault Template Status
register (47513) indicates whether or not that fault number specifies a recent fault (one of 12 stored
faults). If so, the Fault Template Status register value is the fault number. Otherwise, it is zero and all FLT
template values will read zero.
The Fault Indicator register (47512) value is the fault number (1 - 255) of the most recent fault. The user
may construct his front-end GUI to link this register value into the FAULT SELECTION Template holding
register, thereby automatically associating the FLT template with the most recent fault occurrence.