User's Manual

Rockwell Automation Publication 440G-UM004C-EN-P - August 2020 47
Chapter 7 Application Examples
Figure 31 on page 48 shows an example program. A Dual Channel Input Stop
function block monitors the 440G-MZ safety switch, and a Configurable
Redundant Output function block controls two contactors. This example can
be used as a starting point for implementation; you must incorporate
additional logic that is based on the risk assessment for the machine.
Rung Description
0
With the Test Data output setup set as Standard, an HMI input can cycle power ON and OFF to the
440G-MZ safety switch to recover from a fault, if necessary. Upon powerup, the N.C. contact
automatically applies power to the 440G-MZ safety switch.
1
The Dual Channel Input Stop monitors the outputs of the 440G-MZ safety switch. The DCS block is set
for automatic start on powerup (cold start) and automatic restart each time the switch is locked.
2
The output of the DCS in Rung 1 provides a tag that shows the input 440G-MZ input status is OK. This
tag is used in Rung 4 to enable the Configurable Output to be reset.
3
A momentary contact from an HMI input starts a short on delay timer. HMI input must be held long
enough for the timer to expire. This timer is intended to help prevent inadvertent reset. The preset
value can be adjusted to suit the application.
4
When the timer is done, the OSF_Storage_Bit is set. When the HMI_CROUT_Actuate button in Rung 4 is
released, the OSF_Storage_Bit goes LO and the OSF_Output_Bit goes HI.
5
When the OSF_Output_Bit goes HI, the CROUT_Actuate tag is set. The CROUT_Actuate tag is self-sealing
because the OSF_Output_Bit is HI only momentarily.
6
The GMZ_Crout block is set for negative feedback. The CROUT block output cannot go HI unless the
external contactor status at Feedback 1 and 2 is HI.
7 The two CROUT outputs turn ON the ArmorBlock outputs, which energize the external contactors.
8
From an HMI input, you can lock or unlock the 440G-MZ safety switch. The HMI input must be a
maintained switch.
9 Notify the HMI if a fault is present on the DCS block.
10 An HMI input can reset the DCS if a fault is present.
11 Notify the HMI if a fault is present on the CROUT block.
12 An HMI input can reset the CROUT if a fault is present.