Melsec-Q/Qna/Qnas-Series Plcs - Omron EJ1 User Manual

Connecting More Than One HFU
Operation and
Precautions
5-2-2

MELSEC-Q/QnA/QnAS-series PLCs

1,2,3...
158
■ Read/Write Period for PLC Memory
When more than one HFU is connected, communications will be performed in
the following order according to communications unit numbers. The read/write
period for PLC memory will thus be relatively long in comparison to the read/
write period for a 1:1 connection.
0 1 2 ... Max. communication unit number
Or, 32 33 34 ... Max. communication unit number
■ Startup
When the power is turned ON, communications will be started in order of the
communications unit numbers.
■ Power Interruptions
If power is interrupted to one HFU, communications will still continue for the
other HFUs.
Up to eight Advanced Units (HFU) can be connected to one communications
port on a Serial Communications Unit. Use the following models when con-
necting more than one HFU.
Serial Communications Units Channel 2 of QJ71C24N
EJ1N-HFU
1. Connect the EJ1 and PLC.
Always set the communications unit numbers of the HFU in order from 0
through 7, or 32 to 39 if using a version
cations unit numbers of the Basic Units connected to each HFU to a differ-
ent communications unit number than the HFU. (This restriction does not
apply when the communications unit number for the HFU is set to a num-
ber from No. 32 to 39.
■ Example
The communications unit number of the Basic Unit is set to a number from
0 to 31, excluding 1.
Set the communications unit number of another HFU to 0, 2, 3, 4, 5, 6, or
7, i.e., any number other than 1. One HFU can control up to 32 Basic Units.
When connecting 16 or more Basic Units, use distributed placement be-
cause 16 would exceed the maximum number of side-by-side connections.
0
QJ71C24N-R4
Channel 2 of A1SJ71QC24N
Channel 2 of AJ71QC24N
AJ71QC24N-R4
EJ1N-HFUA-NFL2
EJ1N-HFUB-NFL2
V1.2 Unit, and set the communi-
V1.2 )
Section 5-2
1 ...
32 33 ...
V1.2