Maple Systems OIT Family (ASCII) - Manual (Page 17)

A maximum of 25 register monitors can be displayed on each screen. If more than one regis-
ter monitor is on a screen, each register monitor is updated by the OIT in continuous succes-
sion as rapidly as possible. Therefore, the update rate of each register monitor is determined
by the number of register monitors on the screen. For more information on register monitors,
refer to “Register Monitors” in the Features chapter.
D (Data) Registers
The data registers range from D0 to D1023. These registers are 16-bit registers which can be
read/written to in single bit, byte, word, or double word formats by the ASCII host or the OIT.
When the OIT operator changes the value in a read/write register monitor, the new value is
written to the appropriate data register as follows (the examples assume writing to D0):
• When the register monitor is Long or 8-Digit BCD format, the 32-bit value is stored with
the least significant word in D0 and the most significant word in D1. For example, if
12345678 is written to D0, then D0=5678 and D1=1234.
• When the register monitor is Signed, Decimal, 4-Digit BCD, Bank 16, or ASCII Char format,
the 16-bitvalue isstored entirely in D0.For example, if1234is writtento D0, thenD0=1234.
• When the register monitor is Bank 8 format, the 8-bit value is stored in the least significant
byte in D0.
Note: The most significant byte in D0 does not change. For example, if 56 is written to D0
when D0=1234, then D0=1256.
• When the register monitor is 1/0 Coil, On/Off Coil, or ASCII String format, the 1-bit value
is stored in the least significant bit of D0.
Note: The other bits in D0 do not change. For example, if 1 is written to D0 when D0=9878,
then D0=9879.
C (Coil) Registers
The coil registers range from C0 to C1023. These registers are single bit registers which can be
read/written to in single bit,byte,word,ordouble wordformats bythe ASCII hostortheOIT.
When the OIT operator changes the value in a read/write register monitor, the new value is
written to the appropriate coil register as follows (the examples assume writing to C0):
• When the register monitor is Long or 8-Digit BCD format, the 32-bit value is stored with
the least significant bit in C0 and the most significant bit in C31. For example, if 12345678
is written to C0, then C0-C3=8 and C28-C31=1.
• When the register monitor is Signed, Decimal, 4-Digit BCD, Bank 16, or ASCII Char
format, the 16-bit value is stored with the least significant bit in C0 and the most
significant bit in C15. For example, if 1234 is written to C0, then C0-C3=4 and
C12-C15=1.
• When the register monitor is Bank 8 format, the 8-bit value is stored with the least
significant bit in C0 and the most significant bit in C7. For example, if 12 is written to C0,
then C0-C3=2 and C4-C7=1.
• When the register monitor is 1/0 Coil, On/Off Coil, or ASCII String format, the 1-bit value
is stored in C0.
Operating Mode
The ASCII Slave protocol can be programmed to operate in one of two operating modes: Interac-
tive or Network. These modes affect how the OIT sends function key ASCII strings to the ASCII
16 OIT Family Operation Manual (ASCII)
1010-0088, REV02