GE GFK0579B user manual Reference View from a Remote Drop, Configuration Limits

D

Conversely, it is possible that a PCM, GDS, or ADS module contains data which it wishes to pass to the host, or that it requires data to be supplied by the host. To pass data to the host, some %I or %AI memory which is not used by I/O modules must be included in the remote drop I/O map; the PCM, GDS or ADS will then be able to deposit data there, and that data will automatically be transported to the host. To receive data from the host, allocate some %Q or %AQ references within the remote dropI/Omap.

Configuration Limits

There are two configuration limits that must not be exceeded:

HThere must not be too many option modules in the remote drop. This is explained in chapter 1.

HThe I/O configuration data must not be greater than 4500 bytes total. This amount of configuration data will never be reached in a remote drop where all of the I/O modules are included in the Remote I/O Scanner's I/O map. Turn to appendix B if the remote drop drop will have I/O modules configured outside the I/O map, and controlled by option modules in the remote drop.

Note

If you store (as described in Step 4) a configuration which has too many option modules, or which contains too much I/O configuration data, the Remote I/O Scanner will generate an ªIllegal Configurationº error message. If there was an earlier configuration previously stored to the Remote I/O Scanner, it will be DELETED, except for the Device Number, baud rate, and the remote drop ID.

Reference View from a Remote Drop

From the remote drop, Reference View shows the references assigned to each module, by memory type.

	____ D I S C R E T E				I N P U T ( % I ) V I E W ______
	TOTAL I+Q: 352					HIGHEST REF CONFIGURED: 160
	REFERENCE	PHYSICAL	IO		MODULE
	START ± END	ADDRESS	TYPE		TYPE		DESCRIPTION
___________ _________ ______ ________ __________________________
	00001±00016	0.2		90±70		I AC 16	INPUT 120 VAC 16PT ISOLATED
00017±00032		0.3		90±70		I AC 16	INPUT 120 VAC 16PT ISOLATED
00033±00064		0.4		90±70		I DC 32	INPUT 24 VDC 32PT
00065±00096		0.5		90±70		I DC 32	INPUT TTL 32PT
# 00097±00128		0.6		90±70		I DC 32	INPUT 12VDC 32PT POS/NEG LOGIC

In this example, the Remote I/O Scanner is assigned references %I00001 to %I00097. It is within this range that the PLC will accept inputs from modules in the remote drop. However, as the configuration display shows, one input module in the remote drop has been assigned references above %I00097. Any # characters in the left of the screen indicate I/O references which are outside the range configured for data transfer with the PCU. This may be done deliberately in certain applications.

Appendix D Logicmaster 90±70, Release 3: Remote Drop Configuration Instructions 149