selection of s71500 cpu

Hi,

I have a tender where below specification is given.

which plc i should choose in s71500.

PLC CPU module should have the provision for Ethernet TCP/IP RJ45, Modbus, and USB Port connectivity for interfacing with the SCADA/PC .

PLC shall have: (a) separate Power Supply module of 24-48 VDC isolated, of 30 Watts minimum, placed on 1st slot of the rack and (b) CPU separately placed on the second slot of the main rack. CPU Shall be powered by the internal power supply via rack.

Thanks

BALAKRISHNAN92

Hi,

I have a tender where below specification is given.

which plc i should choose in s71500.

PLC CPU module should have the provision for Ethernet TCP/IP RJ45, Modbus, and USB Port connectivity for interfacing with the SCADA/PC .

PLC shall have: (a) separate Power Supply module of 24-48 VDC isolated, of 30 Watts minimum, placed on 1st slot of the rack and (b) CPU separately placed on the second slot of the main rack. CPU Shall be powered by the internal power supply via rack.

Thanks

You can get part numbers if you use the selection tool [https://mall.industry.siemens.com/tstcloud/#/Start]. 

No S7-1500 PLC has a USB port. This may be a left over Rockwell processor specification. Other than that a CPU1511 with 60W power supply should fit into the specifications. On budget an ET200 with S7-1500 processor would do, if it was not for the way the CPU being in slot 1 was specified.

Someone can get into trouble if the specifications are adhered to without insight. For security I would add an Ethernet card. The CPU can handle the Modbus TCP communication but it is best in my view to not connect the CPU directly onto a PC network.

Or were they looking for Modbus RTU / ACII .. ?

The lowest level S7-1500 1511-1PN meets the specifications, albeit the "Should Have" USB port for SCADA.

Technically, the PSU sits in slot "0" and the PLC is in slot "1" But this is just semantics.

I've usually found that the people who write the tender specifications have very little idea on what's truly required.