PLC 2 Flashcards
What is floating master?
Processor holds token and gives it to another processor who wants it.
What is token passing?
Token is passed from the lowest node number to next number. Can only hold token limited amount of time.
Data Highway Plus - Up to how many stations can a token passing network have? How is it numbered?
Up to 64 stations, 0 to 77 octal
Data Highway Plus - What cable is built a twisted pair with a shield?
Belden 9463
Data Highway Plus - Cabling may be installed in what two ways?
Daisy chain and trunk line/ drop line
What is the industrial ethernet of siemens?
ProfiNET
Most I/O communications are a slave master relationship; true or false?
False: Most I/O communications are a MASTER SLAVE relationship
How does master slave operation work?
- The PLC or master scans the remote devices for data
- It reads input data and writes output data
What does bit shift do?
Shifts individual bits in an array to the left or right.
What data type must Bit shift use for its array?
DINT
What is the .UL bit in a Bit Shift instruction?
That is the unload bit. This contains the value of the last bit shifted out.
What does the Bit Shift use to load a bit into the array?
Source is the value to be loaded into the array
What happens to the rest of the bits in an array if you are only shifted 7 bits?
It ignores the rest because you only chose to shift 7 bits
You want to copy an array to another array, what instruction should you use?
COP (copy instruction) or FAL instruction
Parts are being loaded into a warehouse bay each one has a unique
serial number associated with it. What instruction can I use to keep
track of these parts?
LIFO unload (LAST IN FIRST OUT)
A conveyor belt has a number of stations. I need to keep track of which stations have parts at them as the conveyor belt moves. What instruction can I use to keep track of these parts?
BIT SHIFT!
What instruction allows PLCs to read/write to/from each other?
Message Instruction (MSG)
What is the data type of a MESSAGE instruction?
Message Control Tag
Can you using the same MESSAGE tags for more than one MSG instruction?
No
In the configuration tab of the message instruction - If reading from a plc what should you put in the source element?
The target PLC tag you want to read which is usually an array
In the communication tab of the message instruction - What goes in the path option?
The necessary information for the PLC to connect to the target PLC
When talking to ControlLogix to ControlLogix, what does this mean:
LocalENB, 2, 192.168.1.30, 1, 0
◦ LocalENB is the name of your Ethernet Card
◦ 2 indicates Ethernet/IP
◦ 192.168.1.30 is the IP address of the other PLC
◦ 1 indicates communications across the backplane
◦ 0 indicates the slot of the processor
When talking to ControlLogix to CompactLogix, what does this mean:
LocalENB, 2, 192.168.1.30
◦ LocalENB is the name of your Ethernet Card
◦ 2 indicates Ethernet/IP
◦ 192.168.1.30 is the IP address of the other PLC
When talking to CompactLogix to CompactLogix, what does this mean:
2, 192.168.1.30
◦ 2 indicates Ethernet/IP
◦ 192.168.1.30 is the IP address of the other PLC
