Micromod Micro-DCI: 53IT5100A Indicator/Totalizer - Manual (Page 70)

B.1.3 MESSAGE TYPES
The types of messages that are sent between the host or SUPERVISOR-PC and the Datalink net-
work instrument are formatted as follows:
HOST OR SUPERVISOR-PC TO INSTRUMENT:
1. INTERROGATE - This message requests up to 20H consecutively stored bytes, beginning at
the specified memory address location of the addressed instrument.
01111110 E0H + I.A. NUM LO ADD HI ADD LRC
2. CHANGE - This message sends up to 20H bytes of new data to the addressed instrument.
01111110 A0H + I.A. NUM LO ADD HI ADD Data 1 XXXXXXXXX Data N LRC
3. CHANGE BITS - This message alters only the specified bits in the specified bytes in the ad-
dressed instrument. (NUM = 2n)
01111110 C0H + I.A. NUM LO ADD HI ADD Mask 1 State 1 XXXX Mask N
State N LRC
4. ACKNOWLEDGE - This message signals the addressed instrument that its last echoed
change message was received correctly; the instrument performs the change requested.
01111110 80H + I.A.
INSTRUMENT TO HOST OR SUPERVISOR-PC:
1. RESPONSE - This message furnishes the data requested by the INTERROGATE command of
the Host or SUPERVISOR-PC. It is also used to echo back the previous CHANGE message of
the Host or SUPERVISOR-PC.
01111110 20H + I.A. NUM LO ADD HI ADD Data 1 XXXXX Data N LRC
53IT5100 Indicator/Totalizer
B-4