ProSoft Technology PTQ-PDPMV1 - Manual (Page 208)

Hot Standby Support PTQ-PDPMV1 ♦ Quantum Platform
User Manual PROFIBUS DP Master Network Interface Module for Quantum
Page 208 of 306 ProSoft Technology, Inc.
August 12, 2014
%SW61.4: This bit is set = 1 whenever a logic mismatch is detected between the
Primary and Standby PLCs. This means that either the MID, CID or LID is
different on the two PLCs. Under this condition, if bit 13 of the Command
Register is set = 0, bit 1 of the Status Register will be set = 1.
%SW61.5: This bit identifies the order reported by the copro at start time
depends on the range of the MAC addresses.
 If the A/B designation is A, then bit 5 will be set = 0.
 If the A/B designation is B, then bit 5 will be set = 1.
%SW61.14: If set = 1 it indicates that a logic mismatch has been detected that
disallows Unlocated Variables to be transferred from Primary to Standby. This
feature was canceled for UNITY V1.1 because it was determined that a
switchover with a partial application context posed too great a hazard.
%SW61.15: If set = 1 it indicates that the Copro device is set up correctly and
working.
How the PTQ Module Detects a Switchover
The PTQ module and Master bus scanner will react within 100 ms to 300 ms
when the PLC changes its state. The PTQ module reads the PLC status in word
102 (%SW61) of the configuration table with every scan.
Crossed Status Information
The ping message communicates status information between the active and
remote (passive) Masters, and vice versa.
A part of this "crossed status information" (CSI) is presented in the "HSBY
Remote status HSBY Nr of remote slaves" registers. These registers are updated
every time new status information is received from the counterpart. Polling for
new status information takes place every TA ms.
The PTQ module application forwards this information to the Quantum processor,
which, in turn, determines by user application whether or not a switchover should
be carried out.
The following illustration shows how CSI is communicated between the two
Masters and how it is displayed in the Field bus specific area of the DPRAM.