Lighthouse PLCs, Inc. : Automation Forum
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Mr. Rankin,
Thank you for the good questions. Please find my answers (in bold) following your questions.
1) Please confirm that the EH-CPU448 has been replaced by the EH-CPU548.
==> Yes, EH-CPU548 will be the replacement for EH-CPU448.
2) Is the only difference between the EH-CPU516 and the EH-CPU548 the number of expansion racks (2 versus 4)?
==> No, the EH-CPU516 has 16kStpes of program memory and EH-CPU548 has 48kSteps. This and the No. of expansion racks is the only difference.
3) Is the LIBAT-H used solely for the clock and the protected memory?
(What else happens if it is eliminated?)
==> Yes, this is the only use for the battery. If the battery is empty, the rely time clock will not continue working during power off, the retentive memory will be lost and the Error LED will be blinking.
4) If we do not use the clock function, can we use the EH-MEMD for the protected memory and eliminate the need for the battery?
==> Yes, this is possible but the handling of EH-MEMD is little complex compared to standard WM/WR access.
5) Will the EH-MEMP handle the large capacity of the EH-CPU548 (w/ 48k Flash)?
==> EH-MEMP yes, but not EH-MEMD (limited to 16kSteps).
6) What is the EH-MEMD used for? (What is its purpose – only having program capacity of 16k steps)?
==> EH-MEMD was developed while EH-CPU316 was the CPU with the biggest memory, therefore the memory capacity is limited to 16kSteps. But the use of EH-MEMD is for data storage and for this purpose 384KWords are available on EH-MEMD beside the 16kSteps.
7) What can you tell us about the EH-HMEM05 (0.5MB Flash memory expansion)?
==> Memory expansion for smaller size EH-HMI (EH-TD10....).
What can you tell us about the EH-HMEM80 (8MB SSFDC Memory Card)?
==> SSFDC memory card for all EH-HMI touch panels and EH-OP20/30. Capacity 8MByte, 1 pcs. is delivered with each HMI.
9) In a unusually large and extremely complicated project, we have used up all available Timer points, and nearly all the Counter points for a program running in a EH-CPU316 processor. We need to know if the Extended Timer available in the EH-CPU548 will provide us with additional timers? Can you give us any details – like how they are used?
==> Add. Timer TM is available in EH-CPU448, 516 and 548. 2048points with time base 10ms.
I hope this helps with your project.
Regards,
Arnold Rupperath
Hitachi Europe GmbH
