Why is redundant analog output module is only half the current output of each channel .......... 2011-01-29
Redundant analog output as a template, just way to use the current output. Two redundant analog modules connected in parallel together to provide drive current for the actuator. When using redundant analog modules perform control tasks, each template provides the necessary current in the current half of the output current. Failure if any of them a template, then the fault will be detected by the system and take appropriate action. At this point all the other output template output drive current. In case of failure, each analog output module of the surge current does not exceed the current maximum of 50%. If the redundant analog fault a template in the template, then the current output current of the actuator will be reduced to half the normal output current, and quickly picked up the next program cycle to normal. Redundant output of each template will output a minimum of about 120 μA current (a total of approximately 240 μA current) used to ensure there is always a very small positive output. Replacement value of the configuration will lead to 0 mA minimum output. Must use the "Redundant IO" function library provides function blocks to control the analog output module's output. You can "Start> Siemens> Documentation> PCS 7 - Function Manual Fault-tolerant Process Control Systems", or block access to the online help system in the corresponding help information. Maximum fault detection time depend on the template cycle OB (updated template image area allocated OB). Cycle OB should be selected in accordance with the analog output module connected to the actuator response time to choose, its response time must be less than the actuator. If the configuration of the image area is updated too slowly, or greater than the actuator response time, you must re-configure the image area refresh cycle, place it in a more high-speed image area. In addition, used to control the analog output of the function block must also be set to run high-speed operation. Must use CH_AO channel driver blocks and template driven to operate the analog template. Template-driven in the activation of "Generate / Update Module drivers" feature automatically generated. MODxx function block will be automatically installed in the Chart in with @. Users can not tamper with the operation of the template-driven order of function blocks. Users need to manually add the channel to the CFC drive in the block. If the user changes the channel scan feature driven cycle, need to re-activate when compiling CFC "Generate / Update module driver" option, to tell the system to re-locate the template driver is installed and running order. Note: |