Specifications

42
3964 Procedure Section 5-6
Access to the PLC occurs via:
Byte address MB Description
Byte address +0 MB12 Write Coordination Byte
Byte address +1 MB13 Message Channel Low byte
Byte address +2 MB14 Message Channel High byte
Byte address +3 MB15 Function Key LED 1 to 4
Byte address +4 MB16 Function Key LED 5 to 8
Byte address +5 MB17 Function Key LED 9 to 12
Byte address +6 MB18 Function Key LED 13 to 16
Byte address +7 MB19 Function Key LED 17 to 20
Byte address +8 MB20 Function Key LED 21 to 24
Byte address +9 MB21 Function Key LED 25 to 28
Byte address +10 MB22 Function Key LED 29 to 32
Word-structured Memory Mapping
The data area comprises a maximum of 6 words or 12 bytes.
Example: The cyclic data area is set to DW21 in the programming system.
Word address DW High byte Low byte
Word address +0 DW21 Write Coordination Byte Reserved
Word address +1 DW22 Message Channel High Message Channel Low
Word address +2 DW23 Function Key LED 1 to 4 LED 5 to 8
Word address +3 DW24 Function Key LED 9 to 12 LED 13 to 16
Word address +4 DW25 Function Key LED 17 to 20 LED 21 to 24
Word address +5 DW26 Function Key LED 25 to 28 LED 29 to 32
5.6 3964 Procedure
To initiate the communication setup, the active partner will transmit the signal STX
(02h) upon which the partner will have to respond with DLE (10h) within the spec-
ified acknowledgement delay period (2 s).
Subsequently, the procedure data are transmitted, the receipt of which is mon-
itored by a character delay time (220 ms).
After the data have been transmitted, the passive partner will acknowledge the
receipt with DLE.
In the event of errors, the passive partner will transmit a NAK (15h).
In the event of errors during the communication setup, the active partner will make
up to 3 attempts to establish the communication.
If the passive partner transmits a NAK after receipt of the data, the active partner
will make up to 6 attempts to establish the communication and to transmit the data.