Omron CPM1 Programming Manual

17
Basic PC Operation and I/O Processes Section 1-2
1-2-2 Hold Bit Status
Make the settings shown below to determine whether, when the power supply
is turned on, the Forced Status Hold Bit (SR 25211) and/or IOM Hold Bit
(SR 25212) will retain the status that was in effect when the power was last
turned off, or whether the previous status will be cleared.
The Forced Status Hold Bit (SR 25211) determines whether or not the forced
set/reset status is retained when changing from PROGRAM mode to MONI-
TOR mode.
The IOM Hold Bit (SR 25212) determines whether or not the status of IR bits
and LR bits is retained when PC operation is started and stopped.
!Caution Do not use the I/O Hold Bit Status and Forced Status Hold Bit Status Bits
(DM 6601) when the power to the PC is going to be turned off longer than the
memory backup time of the internal capacitor. If the memory backup time is
exceeded, memory status will be unstable even if the I/O Hold Bit Status and
Forced Status Hold Bit Status Bits are used. Unpredictable results may occur
if operation is attempted with unstable memory status.
Note 1. The memory backup time of the internal capacitor varies with the ambient
temperature, but is 20 days at 25
°C. Refer to hardware specifications for
more details.
2. The memory backup time assumes that the internal capacitor is fully
charged before power is turned off. Fulling charging the capacitor requires
that power is supplied to the CPU Unit for at least 15 minutes.
1-2-3 Program Memory Write-protection (CPM1/CPM1A Only)
In CPM1/CPM1A PCs the program memory can be protected by setting bits
00 to 03 of DM 6602 to 0. Bits 04 to 07 determine whether Programming Con-
sole messages are displayed in English or Japanese.
Note DM 6602 itself can still be changed after the program memory has been write-
protected by setting bits 04 to 07 of DM 6602 to 1.
15 0
0 0
Bit
DM6601
SR 25211 setting
0: Clear status
1: Retain status
Always 00
SR 25212 setting
0: Clear status
1: Retain status
Default: Clear both.
15 0
0 0
Bit
DM6602
Programming Console messages
0: English
1: Japanese
Program memory
0: Not write-protected
1: Write-protected
Default: English displays, not write-protected
Always 00

Omron CPM1 Specifications

General

Brand	Omron
Model	CPM1
Category	Controller
Language	English