PLC2 to PLC5 conversion

[ckchew666]

Hi,

We are converting a PLC2 system into PLC5. Can the 1771-DR & 1771-AL be reused? If not what is the engineering involved? Please guide. Thanks.

Regards,
CK Chew

 

[PhilipW]

The 1771-AL modules will need to be replaced with 1771-ASB's. In order to access a remote chassis the the PLC2 used a parallel style of network connection that pre-dates the use of Remote I/O in the PLC5. For this reason the 1771-AL is completely incompatible with the PLC2 processors.

The 1771-DR module is so old it doesn't even appear in current documentation, but from memory I think it was an intelligent I/O module that allowed for a limited amount of I/O logic processing onboard the module, without the need for the processor to be involved. The main reason why this module existed in the days of the PLC2 is that scantimes in the PLC2 could be so slow that the 1771-DR was sold to allow a limited amount of high speed logic to be handled.

When you upgrade the system to a PLC5 if you put the I/O modules associated with any high speed logic in the local chassis of the PLC5 processor, then the scantimes should be fast enough not to need the 1771-DR any more.

 

[PhilipW]

Ooops...delete the bit in my last post re 1771-DR. I was thinking of some other old module. What I stated is correct, but NOT relevant to the 1771-DR.

The 1771-DR is a line driver card that extends the PLC2 serial port distance out to 5000ft. It too is no longer needed in the PLC5 system because the DH+ ports will happily network together multiple processors out to similar distances (3000ft).

 

[ckchew666]

Hi,

I think 1771-DR is a high speed logic controller module. still selling now. but 1771-al no more. anyone can clarify?

 

[ckchew666]

Found out that 1771-DR can be reused. 1771-AL must change to 1771-ALX.
Thanks,

Regards,
CK Chew