Remote-processing RPC-330 Manuel d'utilisateur télécharger pdf (Page 19)

RAM MEMORY SECTION 5

Page 5-2 RPC-330

To install a new memory chip:

1. Turn off power to the RPC-330.

2. Remove the memory chip from U5.

3. Orient the chip so pin 1 is towards the inside.

If installing a 32K RAM, place the chip at the

bottom

of the socket (m emor y chip pin 1 goes into

socket pin 3). The top two socket pins in each row

are empty.

If installing a 128K or 512K, install the chip into the

socket.

4. Check and change, as necessary, jum per W 1 to

conform to the new mem ory.

RAM size Jumper W1

32K [1-2]

128K [1-2]

512K [2-3]

BATTERY BACKUP

An optional battery backup module may be installed.

Principal is the same as installing a RAM chip.

WARNING:

An additional modification must be performed to the

DS1216DM module when a 512K RAM is installed.

Contact Rem ote Processing fo r details.

To install a module:

1. Remove the RAM IC in U5.

2. Install the DS1216DM in U5.

3. Re-install the RAM chip into the top of the module.

Battery voltage is approximately 3.0 volts, measured

between pin 16 (ground) and 30 (128K RAM), 14 and 28

(32K RAM), or 16 and 32 (512K RAM) on the IC itself

(not the circuit side of the board). Be sure to power up

the RPC -330 once to a ctivate the batter y backup cir cuit

in the module.

RESERVED MEMORY

Many control systems use process variables that are

operator entered. "variables" in this context include

numbers, strings, arrays, recipes, or formulas as applied

to your application. They are not a part of the variables

used by Basic. Process variables are accessed by PEEK

and POKE type statements.

The upper 512 bytes of mem ory ar e set aside for this

purpose in a 32K RAM system. In 128K and 512K

RAM systems, all of the first 64K of RAM is used for

program and variable storage. P rocess var iables in these

larger versions are stored starting at segment 1 and

higher.

When the combined program and data size exceed 30K,

a 128K or 512K RA M is nec essary. Additional R AM is

necessary when your program has large arrays and / or

string storage requirements.

MTOP should not be used when variables are battery

backed for power off conditions. Basic clears all of

RAM in segment 0 (except for the last 512 bytes in a

32K system) at power up. Store process variables

starting at segment 1 or higher in a 128K or 512K RAM

system or start at address 7E00H, segment 0 in a 32K

RAM system.

STORING VARIABLES IN RAM

Program s and RPBASIC-52 variables reside in segment

0. Data is generally stored in segment 1 and higher (a

segment is 64K of memory). See memory map figure 5-

2. "Data Area" is segment 1 or higher.

PEEK and POKE type commands store and retrieve

values from memory. For example:

20 POKEB1,12,A

puts the byte value of A into segment 1, addr ess 12.

Use the PEEK statement to retrieve the variable:

50 B = PEEKB(1,12)

Accessing reserved mem ory in a 32K RAM system is

accomplished as follows:

100 POKEB0,7E00H,C

120 B = PEEKB(0,7E05H)

1 2 ... 14 15 16 17 18 19 20 21 22 23 24 ... 47 48

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Remote-processing RPC-330 Manuel d'utilisateur Page 19

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